Unfortunately, this really is normal behavior. I think someone else mentioned that if he had stayed with his Mom and littermates that they would be teaching him that he's being too rough but now that's going to be up to you. (sorry)
We got Mia when she was 10 wks old (or so they said) and she acted exactly like your pup. We got Max when he was 12-13 wks old and I don't remember him doing any of this. What a difference 2 weeks can make.
I think the only thing you can do is what you are doing. Use the same command so he doesn't get confused - have something ready for him to chew on - walk/play with him so he gets tired - be patient - and try to enjoy him as much as possible.