Endometriosis?

I was wondering if anyone with endometriosis would be willing to share their story of how they got diagnosed? (What symptoms did you have, how did your doctor find out?) I have been having long, heavy periods, severe cramps, painful sex, spotting between periods, diarrhea when I’m on my cycle, and extreme fatigue for a long time now, and through my own research endometriosis seems to be one of the possible causes. I brought these symptoms up to my gyno (without knowing anything about endometriosis) and she just recommended birth control and said some women have more extreme symptoms and heavier cycles than others. Birth control has helped a little but most of the feelings remain. I plan to go back and ask if endometriosis is a possible cause, I am just unsure of how they look/test for it.