Endometriosis

How can you tell if you should be checked for endometriosis? I'm sixteen, and my period is a lot worse than all of my friends. I know that periods vary for each person (cramping, how heavy your flow is..), but mine seem to be to the point where it's more than just "bad periods." My cramps are so bad (and not just in my uterus area, but also in places like my anus - sorry if that's TMI) that I have to leave school and work. My periods last about two weeks and my flow is extremely heavy (3-4 super plus tampons and a pad every hour). I have been to the doctor and am on birth control and was told this was the best, but she never checked me for things like endometriosis. Which, by the way, runs in my family. Can I at 16 have it?