Menopause at 23???? What else could it be?

Endometriosis is my guess. It's sometimes hard to diagnose - even with all the tests - unless exploratory surgery is done. I hope the biopsy gives you some answers. If it is not endometriosis, then ask for a referral to an endocrinologist. It may not be menopause, but some other kind of disorder than can be easily regulated with a supplement.