I read it years ago and try as I might I can't find it.
It's based directly after the war. Harry blames himself for everyone's deaths and when he finally finds Ginny she blames him for Fred's death. After a while he goes to the Burrow, and then later George also blames him for Fred's death. He then runs away and goes back to the Dursleys' house and cries in his cupboard under the stairs, and then goes to Grimmauld Place and ends up starving himself and almost dying there before Ginny comes and saves him.