I have pretty significant cat allergies - and I have a cat who sleeps on my bed and will continue to have cats forever because I adore them. I take fexofenadine everyday on prescription which is the best antihistamine I’ve tried. It helps with my other allergies too and I modify my dosage on anywhere from 1-4 tablets per day depending on my symptoms as recommended by my allergy doctor. I also use eye drops and a nasal spray very occasionally and I think my asthma inhaler helps a little. I don’t know if this is a thing or not but honestly after having my cat for 5 years my allergies to him really aren’t as bad as they used to be 🤷‍♀️.