Russian Tortoise question?

I just got a male Russian tortoise a few days ago. He and all the others seemed pretty healthy at the pet store, walking around and frolicking in their tortoise-y fashion. But since I've brought him home, he hasn't eaten at all, and he stays in his house 24 hours a day unless I take him out for something. His tank was a bit cool the first day, but since then, we've taken measures to heat it up more. I've given him both salad greens and pellets, and even apple bits, but they're completely ignored. Is this normal for the first few days, or should I be concerned? (In other words, am I just being paranoid? XD)