The poor thing. Hopefully the sumptoms will ease as the pine pollen does.
Mac used to have trouble in the fall when the leave were falling. My vet suggested Benadryl. (generic ok) it really helped and it didn't seem to tire him out as it does me. (see link below for dosage) He didn't care for taking them, but I figured out that a batch of five minute cooking oatmeal firms up like a pudding. I hid the tiny capsule in a nice scoop, which he would effortlessly swallow, not knowing he got medicine.
http://www.walkervalleyvet.com/otc-meds.htm