You can do some kind of test at a doctor’s office (or naturopath) where they measure your IgA, IgG and IgM levels. This costs between $100-250 (US) and requires a few doctors visits.
There is also some kind of “mail in” tests where you mail in a sample and they send back the results.
How did the spit test turn out for you?
I would recommend going to a naturopathic doctor (they can test you at some places) and they will put you on a better diet.
I definitely would change your diet to something else. While it is mostly really good, I don’t think the supplements sound terribly helpful and you need a different plan. A naturopathic doctor can set you on the right course.