I had a thing earlier this year where I couldn't tell if it was a bad cold or bad allergies. So +1 on getting it checked.

I'm weird and none of the non-sedating antihistamines work for more than one season. I'm taking Allegra this year--it makes me fuzzy, but it's working better than Zyrtec or Claratin have recently. Zyrtec doesn't do anything to my attention span, and Claratin makes me a bit fuzzy. (Benadryl doesn't do anything, and it IS a sedating antihistamine. Funny how these things work.) I supplement it by taking a shower (including rinsing my hair) as soon as I get home.