What's the best allergies meds to help deal with Cat dander, etc?

Some antihistamines work better for some people than others so it's good to try a couple and see which is best. Plus some take several days or a week to be effective so give each sufficient time to be useful before switching to the next. Also the cat should not be allowed in the bedroom. Vacuum often and consider using a HEPA air filtering device. Before permanently committing to a cat, maybe you could borrow one from a friend or foster one for the humane society, to make sure all of the methods above are sufficient to keep you healthy. Good luck!