Abdominal, pelvic and lower back pain?

If I bend over, eat something or do nothing I am having abdominal pain around my belly on but that is not constant, however, the pelvic pain and lower left side back pain is pretty constant. I felt sick on Saturday but then got really sick on Sunday night (bathroom upset) and also Monday morning. I have Endo and have gone off BC pills because they were not helping and have been on so many medications my specialist is stumped so I am going med free right now and this is month 2 now. I Am on day 19 of my cycle and my cycle is 30 days pretty much clockwork. I do feel when I ovulate and I did get sick almost everyday when I was off medications, hence going on the BC pills. But they caused so many side effects and after being off and on 14 different kinds in the past 5 years nothing worked. I am super sensitive to meds and think I may need to go back to my specialist buy if anyone has any advice or ideas about what is going on please help.