My mom is deathly allergic to, what feels like, 'everything' under the sun [all meat except for turkey, all dairy products, nuts, most fish, most kinds of beans, eggs, many types of vegetable, etc, not to mention a MYRIAD of environmental allergies - I'm pretty sure she's a Celiac too but she refuses to try the diet...not that I really blame her since being a Celiac AND having those other limitations would make eating next to impossible].
Back when she was eating those things [before I was born] she had alllll kinds of physical manifestations - anorexically skinny while eating a TON, severe severe eczema+other skin stuff, violent mood swings centered around meal times, she was constantly sleepy, and [in her case, obviously this wouldn't have come up for you! Haha] she had had 5 unexplained miscarriages in a row - just to name a few.
Her doctors couldn't figure it out and the only way anything got discovered was she got the allergy picks, reacted to pretty much everything they pricked her with, doctors freaked out , and she went on a serious elimination diet where she only ate potatoes for a month [a predetermined "safe" food], started getting better, then began adding in foods that she hadn't reacted to in the tests - one at a time, one a week.
About 6 months later she got pregnant with me and things went nuts again [just because her doctors had her eat things she was allergic to, to make sure I got proper nutrition]...but I came out mostly fine! Haha
Anyway, she still has mild "issues" but they're survivable issues and she feels pretty good on a daily basis.
And, at least in her case, she has so many sensitivities that her whole 'thing' is actually considered to be an auto-immune disease in and of itself.
Just a thought.
Have you ever kept a food journal?
Is there a time of year when you feel better? Do you feel better statistically inside or outside? Or the same everywhere? Better or worse at home vs somewhere religiously cleaned, like that hospital you went to?