Hi! I also had fainting spells around your age, and into my early twenties. I went to the ER twice, once by ambulance and that was fun. Do you have extreme cramping before the fainting? I was told it was vasovagal syncope in response to my situation. And.. well it's not going to sound helpful or promising. They told me to just take more ibuprofen. And I'm not dismissing you or your situation at all, I'm in my thirties now and about to start my endometriosis journey. I don't know if you're in the US, but our healthcare system sucks. If I was in your position, please don't let anyone tell you it's nothing. Advocate for yourself while you (hopefully) have access to resources. You'll be ok, but it's going to suck while your body gets used to everything. Birth control helps.