I think you should contact your doctor first and see what exactly is happening to your stomach, especially if you have peptic ulcer symptoms and weight loss.
I guess it could be another food intolerance, but it is really hard to say just from the description. To check what product is harmfull to you, you should eliminate one product after another separately...
It is also possible to use potato starch, corn flour, cooked rice or buckweat or some milk/coconut milk/rice milk. It depends of the recipe, proportions of other ingredients and of course desirable taste:)
Usually, one egg - one or two spoons of replacer.
I personal use all of these products, but as I said - according to needs and not all at once...