Have you looked into your diet? Been tested for food sensitives or allergies? Allergies don't typically give you these symptoms, but sensitivities could.
Have you tried a food elimination program? You can try to eliminate a bunch of things at once, and then slowly add one thing back in at a time, or you can take one thing out at a time and see if that helps if you suspect something in particular.
You could also track your diet and your symptoms to see if you can pinpoint any foods that might be causing it. Pay attention to everything - food, drinks, chewing gum, meds. If it goes in your mouth, you should track it.
Since the symptoms vary from week to week, I'd wonder if it's certain foods/drinks/meds that are triggering certain things.