There's something striking about your fic. Very short and intense, like concentrated anguish. I liked it.

Just a piece of advice: you should reformat, apparently the website has eaten the spaces and it makes it hard to read.

Short, but I don't suppose anyone, not even Snape, could sustain this level of anguish indefinitely.

Well-written and believable but hard to read, because something nasty has happened to your formatting. All the spaces after full-stops have disappeared: you need to export and edit to reinsert them.