I wish I had an answer or something more helpful in response but– me too! I wasn’t getting my period so at 18 years old, my OBGYN prescribed me hormones to “induce” my menstrual cycle. It worked, but it has never been a normal cycle. When I am regularly on the pill, I will get my period. As soon as I come off, which I like to do every now and then for hormonal reasons, I rarely will get my period. Every time I go to the gyno, she seems to listen to my concerns but it always comes down to her telling me its because “I run a lot”, giving me a prescription for progestin/”mini-pill”, and telling me I should go back on my BC. Frustrating!! Will update if I find any answers.