She's a lab -- that explains a lot. Personally, I would NEVER get a lab or a jack russell terrier. Way too much energy for me!! I have also learned that while puppies are cute, I will never (or at least don't plan to ever) get a PUPPY again.
My current dog was supposed to be about 1-1/2 years old when I adopted her. She ended up being probably around 8 months. She still had some energy but not nearly as much as a puppy. My previous puppy had been a terror. I had her at 8 weeks old and she had to be the worst puppy ever. However, she did turn out to be the most well behaved dog I have ever seen. Everybody would ask me how I trained her to be so good. I think it's just that I had to give her my constant attention, because she was so bad as a puppy and always into things.
I lucked out with my current dog. She had been dropped at a shelter in a hail storm. Then a rescue group fostered her. However, she was very well trained (potty-wise). I don't use a crate. It's just not something I like, so she had free reign of the entire house. After about a week, she learned that I would be coming home, and then I would only have occasional accidents to come home to. Good thing is that when she does go during the day, she ALWAYS goes on a throw rug in the bathroom. I always joke that since she knows what the bathroom is for, maybe I can teach her to hop on the toilet and use that!
Good luck with your lab puppy. My friend has a chocolate lab and she is a total nut. She's probably around 5 years old and still crazy. I've heard other people say theirs calmed down after a couple years. I think it all depends on the individual dog.
My first dog was a Lhasa Apso and my current dog is a Lhasa Apso / Shih Tzu mix. I have learned that I like the energy level of Lhasas (as adults). They are very low energy and almost cat-like, meaning they like their time alone and sometimes get annoyed when bothered.
As difficult as it may be at times, just TRY to remain calm and relaxed as much as possible around her. She will pick up on your energy level. Oh, by the way, my sister had a dog before that didn't like to go outside by himself, either. He eventually got over that, but it did take some time. I would imagine a lab puppy will take a while before it is okay being without company.