Endo or Pregnant??

I have long since suspected I have endometriosis. I have an appointment with an OBGYN to get a referral to confirm. My periods are often painful to the point of nonmovement and screaming. Menstridol has been my holy grail, however... the last 3 times I bled, it was very bright red and only lasted a day at a time, over the course of 3 weeks. My periods normally last from 4 days to a week and are very VERY heavy, dark, and full of clots of varying sizes. I'm fairly certain I ovulated around the 15th-17th this month, but I started spotting again today. About a month ago I did take plan b on two separate days, I dont recall when. My usual extreme cramps are now just a minor bother today. Day 1 of my period is always the worst. I did have unprotected sex on multiple occasions with my SO where they finished inside... So what do I do?