If your body won't allow more than a bit of food before nausea and gagging, you may have some gastroparesis. I have had this, myself. I don't know if it's possible to request a gastric emptying test, but that could help. Gastroparesis is when the contents of your stomach don't empty fast enough into your intestines, and I've been learning that it is somewhat common in w/d. It causes all the sxs you are mentioning. There are treatments for it, typically prokinetics. Have you been evaluated for this? It's also called "slow gastric emptying". I feel for you and hope you are getting enough calories. I lost a lot of weight at the end of last year, myself, and could barely eat, and was also afraid I would need a feeding tube ...