Feline (General)

[Guest]

I've searched the archives and can't find an answer to what may be wrong with our 1 1/2 lyr old female calico cat. I'm hoping someone can help:
These symptoms have been slowly coming on. She is lethargic, growls when you pick her up though there is no pinpoint tenderness anywhere we can detect. She acts very hungry when you put food in front of her but immediately vomits (the vomiting almost sounds "airy"). She has lost weight. Her brother is happy, fat, active and playful as she was a month ago.
I got them from horrible conditions as kittens and they were too small to get vaccinations at their checkup (even though they were two months old). I had my fourth child then (turned out to be collicky) and now that things have settled down I realize I did not get them vaccinated!!! I have had many cats and have never not vaccinated before. Can someone tell me what's going on with her?