My tortoise shell calico, Sienna, has not been eating her food and has been vomiting a yellow, foamy liquid. Do these symptoms sound familiar to any particular problem? The vet has done blood work and nothing seems to be wrong. She is also very hostile towards her "brother", Spicey. She growls, hisses and swats at him whenever he comes within two feet of her. This is very unusual. I would really appreciate any feedback anyone has.