Specific Carbohydrate diet is S.C. D. You can google it and find more information. It is a diet for helping to heal the gut after celiac disease. A book about it is called, Breaking the Vicious Cycle. I found the food satisfying and delicious. I have no problem eliminating soy. Eat meat, vegetables, nuts (if tolerated) and I hope it will help you get better, but if it isn't the whole answer, don't give up.
I also suggest they check for parasites (stool test). I know from personal experience these can damage the small intestine.
Have you tried Digestive enzymes. When the small intestine damage, the villi can't do their job of telling the pancreas to fire. This was told to me of my functional medicine nurse. The digestive enzymes can help to break down your food until the villi heal enough to do their job.
I would also suggest looking for other allergies that may be giving your trouble.
I don't want to over-whelm you by making you think that you need to do everything at once, but only to give you a starting list of things to consider and do when you are ready.