Warnings: AU as of OOTP's Department of Mysteries fight.
He was drowning. The waters were churning, curling, crushing; the weight of his guilt burdened his shoulders with constant reminders of his disgrace, his failure. Every time he found purchase on the sharp, rocky cliffs of life, he was flung back off with vicious force, one resounding word echoing in his brain. If, if, if…
It was his fault that Sirius fell through the veil, that Ron was strangled to death by the grasping tentacles of the Unspeakable's disgusting experiments. The knowledge of Hermione's constant fight against the icy fingers of death, the loss of Ginny's hand, and Luna's leg—it all came back to his stupid decisions to play the hero.
His stupidly, naively loyal friends and his stupidly, lovingly loyal godfather—none of them would have been there if he had just listened, if he had put aside that idiotic Gryffindor tendency to leap without looking and drudged up the Slytherin instincts he'd buried so deep inside.
It was all his fault.
Harry released the air he withheld, breathing in biting flood of his guilt, and filled his lungs, his veins, his memories with the chilling burn of his inadequacy. He drowned.