Alwiene

You might want to look into oxalate sensitivity. Can cause a lot of pain and is sometimes the reason people with celiac don't completely improve even on a gluten-free diet.

You might want to try Mucuna Prurienes. My experience is that when I get glutened my dopamin levels drop causing a part of the exhaustion and brain fog. Mucuna contains L Dopa which will up your dopamin levels. For me it helps to feel a bit less exhausted and depressed and clear up my mind a bit when I get glutened so maybe it can help you with the brain...

Do you still eat gluten free wheat starch? That might be a problem. Also some of your symptoms make me think of histamin intolerance, you might want to read into that.

A bit late but maybe my answer can still be helpful. The caramel coloring and citric acid you are talking about are both (if not natural) made of corn. Corn in itself is gluten free but some do respons to it and there is a facebook group with people who are not celiac but do react to very small amounts of corn and corn derivates. Since corn is gluten free...