+1 on allergy testing and treatment.

I take antihistamines and Singulair (leukotriene blocker) for breakthrough symptoms and for the many things for which there's no allergy treatment, but they don't come close to the relief that immunotherapy gives me. Without exaggeration, I could not function whatsoever during peak ragweed season (3-4 weeks in late summer) or peak cedar season (2-3 weeks in early spring) until I started getting shots.

Also try a challenge diet. It's your total allergic load that determines how bad your symptoms are.