Yes, the swollen and on "fire" brain is a problem I can 100% relate too. That is my number one most irritating, degrading, tortuous problem I deal with when pois hits. Fortunately for my diet, i haven't experienced that for a year, but than I went on antibiotics, messed up my gut and experienced pois twice since.
That's why I think this problem is soooo closely related to gut health, food intolerances and allergies. Antibiotics are the worst thing you can put in your gut, and that's what I did, now I'm having pois. I'm getting back to my previous self, but healing doesn't happen overnight.
It sounds to me like you have an ongoing inflammation problem. And I think the combination of you being a vegetarian, not eating meat and not having enough calories forces you to eat stuff your body might not be fine with, like quinoa. Are you still eating that? Take my post with a grain of salt but I do have a lot of pois experience regarding allergies. If your pois is related to diet, you should definitely notice it and feel better within a couple of days to a week after eating the right foods.
Regarding the right doctors I am not entirely sure, but you seem to be on the right path. I'd try to get some kind of cyrex food allergy/sensitivity panel or something... If you haven't already.