Well a spay is a big surgery, you are not over reacting atleast I don't think so. It will probably hurt for her to go to the bathroom for a bit. She is probably still in a bit of pain but should be ok in time. Also, she is probably really thirsty because the anestetics makes their tongues really dry and can cause them to thirst excessively but don't let her have too much or she will be throwing it up. Just make to keep her hydrated though.