First, don't panic! You don't know what the OB will say, and it may not be bad news. If the OB says your endo is back, I would HIGHLY suggest finding a specialist who has experience in excision surgery (cutting out the endo, not burning it). You may need to travel, and it may cost a chunk of money, but I really think it's cheaper in the long run than going through all kinds of fertility treatments and surgery after surgery. I went to Atlanta for my specialist. My doctor's name was Dr. Aldee, and he has like a 97% rate of endo NEVER coming back when he performs the surgery, and those who have excision surgery are just ask likely to get pregnant as the general population, it just takes a little longer since the ovaries have to work a little harder. I felt (and still do) feel a lot better than I ever did before I went to that doctor. All of my endo pain now is really pain from adenomyosis, which can't be treated without a hysterectomy.
Anyways, getting back to the point... don't panic. You'll get pregnant, Caitlin. Endo won't run your life forever. Lots of people get pregnant with endo, and I know you'll be one of them.
PS- I hope AF lets up really soon and you feel better. I hate this for you!