Oh you poor thing 
I had similar. Bad cramps that radiated from my thighs, all the way up my back. Extreme nausea - in fact the nausea may have been the worst part
everything way made worse by moving. So taking the necessary toilets trips was awful. This was all whilst on the pill.
I tri-cycled the pill for a while, and it got to the point where I was taking the same day off every 3 months it was that bad on my first day.
Eventually after numerous useless gp apps, and an ultrasound that showed nothing, I walked in and demanded to be referred to the gynae at my local hospital. They did a laparoscopy to diagnose endo and remove any they found (they found some on one of my ovaries), and also put in a mirena while I was under.
My life now is so much better. V occasional mild cramps, and no periods
I do get hormonal spots like a pp said, but fair enough!
You've been referred so hopefully things will move a bit faster now. I had "Internet-diagnosed" my endo before my dr uttered the word 
If it interests you, they was a site I found yonks ago, about the endo diet. Some people believe endo is worsened by some foods, and cutting those out can really reduce symptoms. Not my sort of thing, but may suit you if you can stick to it?
Sorry for epic post
hope you feel better soon x