Excess phlegm and consantly clearing throat

by Joan
(NYC)

I have so much excess phlegm in my throat that I am constantly clearing it (loudly). I'm embarrassed as well as the people I have to work with.

I've tried everything (Mucinex, Zyrtec, my doctor even told me to try acid reducer). He even gave me a prescription for Flonase in case it was a post nasal drip).

Nothing seems to help.

I'm wondering if I suddenly could have come up with some kind of allergy to food. It seems to be worse right after I eat. Could this be a symptom of celiac disease?