Hi Bec,
Please bear with me as I am new to all this
Where I can put my 2 cents on is. Where you say " My GP said there's a strong genetic predisposition in my family " I can comment there.
Most of the girls in my family have been struck by the endometriosis stick. Yep Hee for us. I am from a family with 6 women and 4 of us have been diagnosed with severe endometriosis. The oldest sister has it and my 2 older sisters and myself . I am the youngest in the family. Also, the youngest of twins. We both have it.
The oldest daughter has had 2 children. Myself and the other 2 sisters are of age to prepare for or start conception.
I don't know whether endometriosis has a pick and choose attitude. Because the other 2 sisters who don't seem to have it. Have both given birth to healthy children. And are fine. As I know it is not just about bearing children. They seem to fine during their periods etc. One of them has 5 children.
I was told by a surgeon, that it is stronger if it stems from your mothers side. Obviously your dad is not going to have it ha ha. But if his mother had it. My grandmother (on mothers side) and mother had problems with their cycles.
It just seems it's your luck or bad luck you get it. Your chances are higher , if it is a trait that is in the family.
So i suppose you deal with what you get when you get it. The thing is, is that we support each other through our rough times (with the endometriosis). We all know what each other is going through.
Maybe talk to your sister and see how she is dealing with it. Nothing better than close to home support. Oh, and of course the support/advice from this forum as you know. It's is awesome.

Hope this helps. Sorry for the big rant.

WA_Endo