Out of curiosity, which IUD do you have implanted, the Paragard or Mirena? I have PCOS, which is not the same as Endometriosis or a ruptured overran cyst but can cause also extreme pain. I was having periods every two weeks and I finally had a period where I ended up in the emergency room twice in one day from the pain. The doctors at the ER suggested that part of the problem might be the fact that I had the Paragard IUD, which could cause worse cramping and heavier periods. I had it removed and switched to hormonal birth control. Ever since then my periods have been light, usually only once a month, and the cramping is manageable.

I realize this is anecdotal and may not be helpful to you, so I thoroughly suggest doing some research about your options for dealing with Endometriosis, but I would suggest if you aren't on the Mirena or some other form of hormonal birth control you look into it. The hormones can really help regulate things, in my experience.