I have no words of wisdom but that I am going through the same thing. My lab is 9 months now and is doing what you and everyone else is talking about. The other day he was triggered by walking on a small mound of sand in the road, he started to slip and it scared him. He started to act like a zoomie was coming on, I redirected him to walk across the street, it calmed him for a minute, than we started walking. A couple minutes passed and he was jumping up and mouthing like crazy, I could not get him to stop. I handed him the leash, which usually helps but it didn’t that time. I finally took off my sports watch, which he was nipping at and he carried it home. All full of bites on my forearms we stayed home from our walk today and not looking forward to a walk with him tomorrow. I’m understanding now that adolescent labs are just as hard as puppyhood! I was told by the groomer today it has a lot to do with hormones/adolescence.