Have they done any genetic work-ups on you? My daughter-in-law around the age of 26 went down to about 86 pounds and could eat almost nothing. They even gave her last rights. Every month they would give her dextrose (sugar) IV's (plus other ingredients) to flush out her liver and had her eat basically one food per month. One time was sliced string beans. I wondered if it was a type of PKU but didn't say anything. Eventually, she got to Johns Hopkins and they tested her genetically, she had a form of it and she started to gradually eat foods again, took certain medications, and they instructed her on types of foods to avoid a crisis. She presently is coming out of one; hadn't had one in many, many months but, it could have been some foods she had been eating too much of. All the same digestive symptoms so many write of and like you have..
If she didn't get better, she planned on going to the Mayo Clinic but, the last week she make a dramatic turn-around. She is 42 years-old and it took so many years to find the real problem out. I believe it was only 4 or 5 years ago when the testing was done. Just an idea. Can be so many things like the GMO foods our GI tract just doesn't seem to be able to digest well; many have all kinds of bowel problems from them and try organic foods. If I find any info out from my medical sites I will let you know. Best of luck. Like I said, my daughter-in-law had good help at Johns Hopkins but also believed the Mayo Clinic was very capable, maybe even more so, to help her with the problem that was discovered. Once you know what it is...you at least can treat it correctly. Hope you start to feel better!