@Cori15 Hosts should definitely mention in their listing if they have pets. So hopefully Airbnb can take care of getting you rehoused.
But in the future, please keep in mind that if a guest has allergies or other physical disabilities that the guest should also be pro-active when looking to book an accomodation. In other words, don't just book a place without messaging the host first to confirm they don't have cats or anything else one might be allergic to. It's your health that's at stake, so best not to make assumptions. Doing this could have saved both you and the host a hassle.