It's super easy to be allergic to cedar pollen because it is such a fine pollen. I developed a cedar pollen allergy within a couple years of moving from somewhere with no cedar to a heavily forested area with cedar. No other allergies to anything, I don't think I'm particularly prone. I tried doing the allergy shots for it for a while but it didn't seem to do much. What works is staying inside with the house sealed up and air filters running, or just getting the hell out of town for a month+.