I would see an ENT, your allergist and a neurologist.
I also have allergies and I found out I had an issue with soy.
it gave me head aches and a feeling that i was out of it all the time and if you asked me to repeat my phone number, 50% of the time I couldn't!
Allergist said I was not allergic but had intolerances to it.
The awesome thing about soy.... its in everything! I the only time I can eat anything I want is when I am out of the Country!
Major food intolerances are in general to ; wheat, corn, soy and milk.
Good luck.