Hello! Today I brought in my foster cat and her kittens to be spayed. Before they were spayed, they were all sleeping together, playing together, and eating together without a problem. Mom cat was super affectionate. Now it’s been about seven hours since we got home and they are all growling and hissing at each other and won’t get within a few feet of each other. Mom is even hissing at her babies. None of them are hissing at me though and are letting me pet them. Are they just confused and in pain? What’s going on?