First off, I will tell you that raw feeding does NOT in any way, shape or form have anything to do with aggression of any type. If done properly, it is probably the safest way to feed a dog and the best way to ensure that a dog receives everything that it needs to be physically healthy.
While I would prefer to see a working breed puppy stay with it's litter until it is 8 weeks old, 7 1/2 weeks is not unheard of and is not detrimental to the mental health of a puppy.
At 6 months old, this is still, very much, a young puppy. No, he doesn't know his own strength. You need to teach him the proper way to play. So - here goes. When he tries to bite you, don't speak just cross your arms in front of you and turn your back to him. Will he continue? Probably. Keep your back to him (even if this means turning around in circles) and ignore. He will soon learn that biting makes you extremely boring.
I strongly suggest you get back into some kind of training class. I think that you will find that the biting will lessen as your dog matures IF you keep him learning and his mind busy with other things. This is a working dog, that came from working parents - if he is bored, he is going to find things to do and they probably won't be things you would prefer that he be doing.