What is the best allergy medication to get?

Claritin is weaker than Zyrtec but less likely to cause drowsiness.
Zyrtec is about as strong as Benadryl and less likely to cause drowsiness than Benadryl, but it does make some ppl drowsy.

If Claritin is too weak and Zyrtec makes you drowsy, you will have to reduce your exposure or suffer until you get a prescription. Nasalcrom is OTC and useful for some ppl, but only if its used 4 times daily so this medication does not make sense for ppl who have allergies for many months of the year. It prevents but does not reverse allergy so you have to use it for a few weeks before you feel the difference, unless you start it before the exposure.

In the meantime consider using a Neil-Med sinus rinse, a HEPA vacuum, washing the cats (or cleaning them with Aller-pet) frequently, keeping the cats out of the bedroom. If you keep the windows closed to keep out the pollen (usually a good idea in spring) you will also trap in the cat allergens, so only do that if you also use a good air filter in your bedroom (like the 3m filtrete or honeywell---never use an air filter that makes ozone, please).