Disclaimer: Harry Potter and his world belong to J.K. Rowling. This story belongs to me.

A/N- Hello one and all, and welcome to my new story! I know that I probably shouldn't be trying to write it when I still have incomplete fics on my profile but in my defence, this story isn't going to be very long (probably around three chapters) and I couldn't resist the idea once it popped into my head. I've recently written another Harry/Snape mentor story (which is complete), and it got such a good reception that it gave me the confidence to try my hand at more! I'll do my very best to continue to update my other stories as I have been doing, but for now, I really, really hope you enjoy this newest edition!

~Strength in Weakness~

The Beginning

Harry lay there, unmoving in his pain as the darkness of the dormitory cast moonlit shadows on his shaking form. Sweat poured from his forehead and he groaned, an ache filling his lungs as if his breath had suddenly become ice. Slowly he tried to pull his arm up, clenching his teeth as even the smallest movement caused stabbing pains in his chest. Time taunted Harry as he glanced towards his watch, squinting as he tried to counteract the darkness of the dormitory and his own bad vision.

3.45 am.

Harry painfully pulled himself up in his four-poster bed, trying to desperately smother a hacking cough as his lungs contracted painfully deep within his chest. With a shaky hand, he reached blindly for the half-drunk glass of water that he always left by his bedside, his throat raw and incredibly dry. Another fit came suddenly upon him though, and instead he allowed his hand to fall limply back to his side, knowing that if he tried to pick the glass up now, he'd probably just drop it before he'd even managed to take a sip.

Clenching his eyes shut as sweat ran down his forehead, Harry struggled to regain control of his breathing, his hands gripped tightly to the white sheets that covered his bed. Listening carefully, Harry shoved a hand over his mouth in desperation, trying to contain his erratic breathing, making sure that not even the tiniest sound left his lips, no matter how much it hurt. He didn't want to wake his dorm-mates up.

He couldn't wake his dorm-mates up.

At the moment, no one knew there was anything wrong with him, not even Ron or Hermione, and Harry wanted it to stay that way. This year had been bad enough, what with Umbridge's regime and those disastrous Occlumency lessons with Snape, and he really didn't need anyone to think he couldn't handle everything.

It was the only thing keeping him going.

The trouble was, though, that whatever was bothering him, this illness, was getting progressively worse night by night, and exhaustion was creeping ever closer to his consciousness. Harry wasn't sure how long he could hide his illness from everyone, and desperation tugged at his chest in fear, adding to the ache that was already there. He couldn't handle it if everyone knew how sick he was. Deep down, Harry knew it was stupid; he knew he should get help, but he just couldn't. He needed to handle it himself, if nothing else but to prove to himself that he could. He had felt weak and useless ever since that terrible night in the Graveyard. He needed to be strong now because otherwise...well, otherwise he wasn't sure he could keep going on at all.

At first, it had been easy. By day he was his usual self, joking with Ron and the other boys, teasing Hermione, and laughing when she chastised them. The illness was never as bad in the day as it was in the night-time hours, and only once or twice had he had to suppress a grimace as he felt the pain rear expectedly up in his chest. The weakness never seemed to leave though, and it was only by sheer force of will that Harry was able to push it away and not let it show.

Night was by far the worst. It was only at night that Harry allowed his weakness to get the better of him. Only then did the illness make a true appearance; great wracking coughs, a painful tightening in his lungs. Weakness, exhaustion, pain; all only experienced in the darkness of night. In the darkness where his nightmares haunted him, and Cedric's deadened face taunted him every time he closed his eyes...

Blinking desperately as he swung his legs off the bed, Harry smothered yet another cough as pain overwhelmed his expression and dizziness came upon him. Only in the darkness did he let his careful mask slip, only when no one could see and no one could know. But, with anxiousness almost tearing a hole in his heart, Harry feared that he was going to lose even that small comfort soon, especially if it kept going like this.

His control over his breathing had become worse, particularly over the last few days, and recently he had barely had a full evening's sleep, his nights taken up by self-imposed silent vigils as he waited for the fits to pass.

Shaking himself slightly, Harry pulled himself shakily to his feet. With a quick glance over to the other slumbering occupants of the dormitory, Harry padded slowly and quietly over to the bathroom, holding back a groan as his head swam dangerously. His muscles - particularly those in his chest - ached as he crept through the dormitory, and tiredness enveloped his thin frame, so much so that he had to steady himself against the doorway to the bathroom to stop himself from collapsing to the floor. Harry knew that he was being stupid, that he needed help to get better and that he simply couldn't keep going like this, but his childhood experiences at the Dursleys had taught him differently.

He'd handle it on his own.

Harry could count on one hand the number of times he had received treatment for any illnesses he had suffered as a child, a figure much less than the actual number of times he had been sick. He had always done better dealing with these things alone, and this year it was even more important.

He couldn't afford to show any weakness, not with all the pressure he was under. One crack in his mask and Umbridge would strike; Harry knew it as surely as he knew he wouldn't get any more sleep that night.

Sighing slightly, Harry scooped up some water from the sink and splashed it on his clammy face, his eyes rising to meet his pale and shaking reflection. He had to get a grip on himself. Exhaustion was creeping up on him, but he shoved away the weakness as best he could. He had a long day tomorrow. Defence in the morning, followed by Potions; and it was all before lunch. Harry held back another groan as he made his way slowly back to his bed. Maybe the pain in his lungs would stay away long enough for him to get another couple of hours of sleep.

He doubted it.

Harry picked up the glass of water by his bed, steadying his hands as best he could to counter the tremors in his tired limbs. Gulping the cold liquid desperately, Harry willed his coughs to subside long enough for the water to make its way down his throat. With a trembling hand, he placed the now empty glass back on his bedside table, and tried to lie back on his bed.

Harry sighed wearily, resting his head gently on the pillow as he lay on his back, eyes wide open as he stared unseeing at the ceiling above his bed, his focus largely on preventing the coughs he knew where trying to fight their way out of him. Hopefully, like the pattern had been all week, he would be feeling better by the morning.

Tomorrow would be a long day indeed.

His feet unsteady and his breathing laboured, Harry stumbled into the Potion's classroom the next morning, his mind focused solely on making it to his desk in one piece. Ron and Hermione shot him concerned looks, but he merely gave them a weak smile and turned his attention to his Potions book. They probably thought his state of mind was something to do with Umbridge but in all honesty, Harry had barely noticed that he had been in a defence lesson at all. She had probably mocked him hundreds of times in the last hour, but all Harry had been able to focus on was his own ability to breathe properly.

Recently, it had become much harder.

Harry let out a shaky breath as he opened his book to the relevant page. His vision swam, and heat rose on his face, but he steadied himself on the table until it passed, desperate to just get through the lesson without any problems.

"You alright mate?" Ron asked quietly, his expression a picture of concern. It looked odd on Ron's usually cheerful face.

"Fine," Harry whispered, suppressing more coughs as he steeled himself for the lesson to follow. One more hour and it was lunchtime. Only one hour of Snape to deal with and then he was free.

He wasn't so ill that he couldn't deal with that, right?

The lesson passed in a blur, and in all honesty, had he not been working with Hermione, Harry would have probably blown up his potion long before now. He raised a shaking hand to wipe the sweat from his forehead, shocked slightly by the extent to which the tremors were ravaging his limbs. His lungs felt as if they had been filled with ice, and no matter how often he blinked, blurriness ravaged his vision. He couldn't focus, couldn't breath...

Gripping the desk tightly, partly to hide the shaking from Hermione and partly to hold himself up, Harry closed his eyes, riding the newest wave of dizziness that had come upon him, and praying that he didn't faint. His breathing quickened against his will, and he was sure, even with the fogginess in his brain, that he wasn't getting enough oxygen.

Subconsciously he brought a hand to his chest, desperate to level out his breathing and pull in the air he needed, but it was too difficult and his vision swam as his lungs contracted painfully.

"Harry..." began Hermione but Harry barely even heard her over the sound of his own heart beat pounding loudly in his ears.

Quickly, he dragged over a stool and fell onto it, seconds away from fainting dead on the floor. The hustle and bustle of the classroom meant that most people paid no attention to him, but Hermione, as his partner, certainly hadn't missed it.

"Harry?" she whispered, concern covering her face as she watched her friend grip tightly onto the wooden stool, looking as if any second now he might fall off. "Are you okay? Do you need me to get Professor Snape?"

"No," Harry ground out, his voice a mere whisper as his chest tightened painfully. "I...I...just need...a minute. I'm...okay."

He snapped his eyes shut tight in a grimace of pain, his head swimming dangerously as he clung onto the stool. He wasn't okay. He knew he wasn't okay, but he couldn't bear to let this weakness show; especially in a class that included Snape and all the fifth year Slytherins. There was no way he was going to give them any ammunition against him. He would just have to sit it out here, and hope that Hermione could manage the rest of the potion on her own. He promised himself that he'd make it up to her, once he was feeling better of course. Harry raised a shaky hand to look at his watch.

Only ten minutes to go.

"Just...keep going," he whispered to Hermione, trying to ignore to intense look of concern on her face, a look mirrored by Ron and Neville who were working on the bench next to them. "I'm fine. Please...just...keep going."

"Harry..."

"Please, Hermione," Harry begged, desperately suppressing another fit of coughs. His chest ached with white-hot pain, and heat rose to the tip of each of his limbs. He was burning up. What the hell was wrong with him?

His heart was beating loudly in his chest, far more loudly than was natural, his throat burned and his chest ached. And yet, the feeling was almost nothing, nothing, compared to what he felt when he heard someone come up behind him. Anyone but him...

"Mr Potter," sneered his Professor, the low silky voice immediately telling Harry who it was, even despite his distress.

Instead of answering, or even acknowledging the man's presence, Harry slammed his eyes closed, forcing air into his lungs, hoping desperately that his illness, whatever it was, would disappear in the next ten seconds. He refused to show any weakness to Snape.

"Lazing about are we?" Snape sneered.

"Sir," Hermione began desperately. "Something's wrong with him. He's not well - "

"Quiet, Granger!" Snape snapped.

Harry felt anger rise up in him, momentarily overcoming the pain in his lungs, and before he'd even thought about it, Harry jumped to his feet and span round to face the Professor, anger dancing in his eyes in defence of his friend, even despite his difficulty with even the simple act of breathing.

Harry didn't get much time to consider the foolishness of his actions however, as the breath stopped in his chest. It didn't take long for the rest of the illness to catch up to him either, and before Harry could even say a word, blood rushed to his head, dizziness and pain overcoming him in equal measures.

He couldn't breathe, no matter how hard he tried to pull in the air he knew he needed, Harry just couldn't seem to do it, and it was with panicked eyes that he grabbed at the desk, hoping beyond all hope that he could just stay on his feet long enough for it to pass. He couldn't do it though, it wouldn't come. The loud thudding in his head became louder, almost until he couldn't hear anything else, and red crossed his blurry vision as his face flushed with heat.

It was almost a relief when he felt the blackness come upon him, pulling him into the blissful state of unconsciousness.

Harry didn't even remember hitting the ground.

A/N- Well, I hope you enjoyed that. I'm pretty nervous about this, so I'll ask...does anyone out there want to read more? If Harry's symptoms seem wrong to you (or unlike anything that actually exists in the real world)...well, all I'll say is that there is an explanation. Anybody want to try to guess what that might be? The update may not come immediately (as I stated earlier, I want to make sure I don't neglect my other fics), but it will come in time. Please be patient - I'll do everything I can to make it worth the wait. Hope you liked it, and thanks for reading!