Id say find a decent trainer, one that trains labs. It may cost a litle more but having one that understands and has worked with the breed will benefit endlessly - just to point the training is 75% about you and the rest about your dog, so dont think simply because youve attended lessons your dog knows what its doing (dont take that the wrong way ). If you can find one that doesnt use treats this will help you to realise when your dog is doing what its asked and why - what your doing to make it do what its doing (wanting it to do or not). It really only sounds like pup problems, I dont train every day and my boys cool though if he does start doing his own thing I just go back to regular heelwork and mix in so more difficult commands to keep him keen.