Ive tried with 3 diff labs
and gotten to what seems to be the same point you are cur.
If you believe its taken a lot of patience to this point, it gets worse. IMO there arent but a handful of
people out there that can truly finish a retriever. You may be one of those people. I am certainly not. As previously stated, take some time off may help.
My main recommendation (where I think I went wrong each time) is dont get to close to the dog outside of the hunt. This was impossible for me leading to all my labs becoming just pets. Ive seen some decent retrievers that were house dogs, but basically you need to be the dogs handler, not his best friend.
Another thing to think about in the future is getting a female. They tend to be more even tempered and seem to not mix human signals and emotions like a male.
Keep us updated especially if things get better.
Good Luck