Could I have something other than IBS?

I was diagnosed like a year and a half ago with celiac disease, ibs, and the early stages of endometriosis. For the past several months I have been getting a recurring fever (low-high) accompanied by weakness and sometimes achiness. My Gastroenterologist tested my stool for common viruses but it was negative. I know that my colonoscopy was negative for an ibd a year and a half ago, but this recurring fever is really baffling. Its like I keep getting a stomach virus but I am negative for that virus. This fever is accompanying abdominal pain that can be manageable to excruciating, alternating constipation and diarrhea. No one seems to be able to explain this fever. I also lost some significant weight in the past year. Is it possible for an ibd to be missed or that I have developed one since my last colonoscopy. Its not that I want to have an IBD, (I struggle plenty with my ibs) but I really can't understand this fever.