I agree with your primary. Forteo is unlikely to cause stomach issues. Whatever effects it casuses should go away within 24 hours as the medication (unlike many others) leaves your system quickly. as your primary informs us, you just quit taking it. Tymlos is a similar medication with slightly higher increase in BMD. You could be allergic to one or the other and can readily switch if you had problems with Forteo.
I'm a little older than you are and have been taking Forteo for over a year without adverse effect. I recommend Forteo (all the time, excessively) because I've had such a good experience with it. For some it is intolerable. You lose gains with Forteo when it is stopped, but it is a much slower loss than Evenity or Prolia. And you don't lose lower than baseline. You might though consider getting Bone Markers (CTX, P1NP) to be certain that Forteo is working for you. One set before starting and one set at two months.
Forteo was previously limited to 18 months. Now, patients are extending use to commonly 3 but I've heard of six years. Keep persevering and posting. Let us know what you decide and how it works.
Nausea was signaled in the clinical trials of Forteo. The thinking is that this is caused by shifting calcium levels. It is said that this adverse reaction resolves in the first week as your body adjusts . i never had any, and hope you wouldn't either.
Forteo and Tymlos both build bone. Reclast, all the bisphosphonates and Prolia work by preventing older bone from remodeling. Tymlos and Forteo increase BMD more rapidly. And it is good strong new bone.