The first thing I would do would be to go back to the breeder and smack the crap out of him for selling a puppy before it was at least 7 weeks old. [:@][:@]
Very true it is illegal here to sell a pup at this age! Your pup still needs others to play with so, if he is chewing on you or barking a little that would be normal. So let him get a little age on him before trying to correct him of this.