What do I do to help my baby bunny?

Today I got a baby bunny from a friend who rescued it from a cat. It lost some skin on it's back leg but I was able to clean it and stop the bleeding. Its all bandaged up and seems to be fine but I cannot seem to get it to eat or drink. It can't be more than a week old and doesn't move a whole lot, but I'm worried about it not eating or drinking, what do I do?