Get yourself tested by your doctor or have them refer you to an allergist to get tested
for what you are allergic to. My favorite over the counter medication
for allergies is Zyrtec, I don't have any reactions to it whatsoever and it works faster than Claritin does for me. The doctor may check you for rhinitis, which for the lack of better words is having very little to no lining in your nose, which, in turn causes the mucus to just kind of run out all over the place.