I agree w/ what Karen said.

Action plan:
1. Vet check
2. STOP "dominance" training - it's a very old model, outdated, has been proven NOT to work
3. Start positive reinforcement training. Take several classes w/ the dog.

Find a good place for classes, here:
http://www.apdt.com/petowners/ts/default.aspx

Do group classes, NOT one on one training.

Good luck!