Whats wrong with my puppy?

I have a puppy. i have had him for 2 days and last night he was sleeping on my lap and suddenly he gets up and starts grawling at one of the doors and the wall in our house. and then did a warning back trype grawl and i picked him up to calm him down and he started whinning and howling like someone was hurting him or stepped on his foot or something. and then he bit me on the hand. but he is the sweeties dog ever. he wouldnt ever hurt anyone. afterwords he was really jumpy and shaking.