"Why" this happens, no one has actually come up with an explanation for it yet, but it is a real phenomena. On the surface, your diet "looks" great for a typical celiac who is a male and hungry, with no additional food intolerances. But for some of us sensitive ones, that sort of diet, especially for beginners, with the sugary desserts, the dairy, the soy and the gluten free oat cross contamination from the Bob's Red Mill brand of flours, is not going to work. You're really challenging your damaged innards. Do you know yet, if you are one of the subset of gluten free eaters who still react to gluten free oats ?
As far as I know, I haven't eaten any oats. There aren't any in the Bob's Red Mill flours I've used, at least according to the labels.
I am thinking I will try limiting myself to meat, eggs, veggies, fruit, nuts, rice, and potatoes and see how that goes. That should be easy enough since I've got very little appetite at this point. If the GI problems clear up, I'll know it was something I was eating and then begin the process of reintroducing foods one at a time to find the culprit.
I just wanted to check in here to see whether anyone might be aware of any explanation aside from sudden new and unexplained food intolerances.