I have severe lower (sacral) back pain, necessitating assistance to get out of bed. I have been told that I have IBS, then Crohn's. Water-loss stools X4/day X16 days/month. I was told that I also have RA, but now they are questioning it regarding my GI difficulties. Is there a link? How do you distinguish between IBS, Crohn's, autoimmune disease, etc?