My daughter has been suffering digesting problems since her teens. She is 26 now. She too has had test after test that come back normal. She did have a surgery done on her intestines in her teens. Trying to figure out if what was going on then, is part of what is going on now. Or if the surgery triggered a different set of digestive disorders. She too has tried all different methods of trying to find relief. I am pretty sure she has an autoimmune problem and something going on that is rare and hard to diagnose. When she went through bouts of constipation one thing that did help were colonics (hydro colon therapy). They brought some relief for that part of her health problems. Right now she continues to go from doctor to doctor hoping someone will look outside the box instead of running the same tests. We know what she doesn't have! She too gets very depressed because she is just tired of feeling lousy all the time. It affects every aspect of her life. If it is an option, a place like Mayo clinic would probably be able to diagnose you. We are in the process of trying to get her seen there. I feel for you. Don't give up.