Harry knew at once that Snape's feelings toward him hadn't changed one jot. This didn't worry Harry. It seemed as though life would be back to normal next year, or as normal as it ever was at Hogwarts. (17.201)
Having the fantasy of a perfect home is just that: a fantasy. It's too late to have the picture-perfect home and family that Harry should have started out with. So what he clings to here is the idea of what's "normal." It might seem like attending wizarding school is pretty far from normal, but it's become normal for Harry – at least, the Hogwarts definition of normal has become so for him.