During my journey I have had so many tests to rule things in our out. Still on my journey but SIBO is probably my root cause. I have been tested for parasites, Lyme diseases, scleredoma, h pylori, c diff, candida, pancreatic enzyme deficiency (EPI). Includes stool test for malabsoprtion and several motility studies (egg test and ballon test) . I even did PT for pelvic floor dysfucntion ( did not help me but helps some). My functional medicine test GI Map is probably one of the best one to date but is exensive and not covered by insurance. I just throw this list out there in case any of these test that have not been performed for you yet. If you can get a prescription for Integrative Therapeutics Physicians Elemental Diet that helps me. Often I use it as a meal replacement when I feel too sick to eat. I flavor it with Stur (fruit punch) with Stevia( I do not eat sugar or artificial sweetners) .I blend it with ice (spring water ice cubes I get at Whole Foods). Here is my "mocktail". It tastes pretty good.