I suggest an endocrinologist. Bisphosphonates render the more potent bone building drugs less effective. Tymlos, Forteo and Evenity would be better ways to address really low scores. Insurance may be an issue unless you "fail" another drug, but these companies have patient assistance programs. I got my Tymlos for free.

Hormone replacement might help in your situation but won't be enough to reverse the loss.

Has your parathyroid been checked?

I have osteoporosis and osteopenia, have had for several years. We still need our hormones to be balanced. Biophosphates come with side effects (check those out out and weigh the pros and cons as you’re much younger than I am) and it’s a decision I decided against and along with calcium and other bone building supplements plus weight bearing exercises is what I’ve chosen to do. I improved my scores a few years ago and hope they continue along that path.
Take care .