Try Bananas. They encourage stomach mucus production which might help a little. I think that you are wasting money on L-Glutamine, it will not fix the problem.
You have Increased Intestinal Permeability aka Leaky Gut which causes your body to react to foods just like so many other people including myself.
The foods that you mention that make you feel like shit are highly reactive foods and mostly high protein too. Veggies shouldn't really be a problem, I do not understand why you are having problems with them but avoiding high carb ones might be a good idea. Green veg such as sprouts, cabbage, onions should be easier but even those will be absorbed and you could react to them if your digestive system is highly permeable. All of which will be being absorbed into your blood stream which your immune system will be reacting to.
High dose B12 ie Methylcobalamin can help suppress the immune reaction. It was mentioned on wikipedia until someone edited it out fairly recently. Probably a drug company bod worried about it affecting their profits. It takes high doses of B12 throughout the day, typically 30mg/day. It very significantly reduces joint and muscle pain for me.
parasites are possible when low stomach acid exists but not necessarily a problem unless you are unfortunate enough to eat their eggs. Little to no stomach acid means they do not get destroyed. The drawbridge is down and anything get get in!