What is the best over-the-counter medication for cat allergy sufferers?

I have an awesome cat - despite over a decade of owning her, my allergies to her have increased over time. I get really stuffy, congested, sneeze a lot, and my eyes get red or water a bit. However, she's the best pet in the world and I have no intention to ever get rid of her. What is the best pill / medication I can take for this? I don't mind if it's daily, as long as it's a safe medication with few if any side effects. Hoping people with personal experience can tell me what worked for them and any tips/suggestions. Thanks :)