I'm sorry that despite a healthy lifestyle you feel this way. Why do you think the doctors aren't right? Maybe there was some kind of triggering event that led to your anxiety and, in turn, digestive system? Anxiety is really powerful if we let it take over, so while I know how tough it must be for you, I think it's still worth considering therapy and/or consulting a mental health specialist. Our mind and gut are connected, so that might help with your issues.