Sounds like everything's going as well as expected. Cats often stop eating and drinking when they are under stress, and you correctly surmise this would mean she wouldn't use the litterbox, either. She should start eating and drinking in the next day or two, but in the meantime make sure she doesn't dehydrate (just gently pinch her skin between your fingers, if it snaps back immediately she's fine, if it stays "pinched" for a moment she will need a visit to the vet). You might want to make sure, too, that she isn't peeing on the carpet somewhere, which unfortunately cats also sometimes do when they're stressed!