Does it sound like I have endometriosis?

Let me start off by letting you know that my sister has endometriosis, and my mother had to get a hysterectomy because her uterus would thicken instead of thin. Anyway, I am 25 and have been ttc and off of bc for 18 months. gradually, the spotting before my period has cone earlier and earlier. I now start spotting 8 days before my period. It starts out as a brown discharge, and gradually goes to dark blood. And then, i get a full period. So, im bleeding about 13 days a month. Every 3rd period completely kills me. My cramps are so bad that I am squating at work in pain. My rear end and tail bone ache. I get headaches and my eyes get fuzzy. Oh ya, and when I try to have sex right before my period is due, it hurts and is uncomfortable...

I have a doctor appt on the 22nd...

Any advice or questions I should ask my doctor?

Does this even sound like endometriosis, or am I being a drama queen?