Why does my cat do this?

I have a 7 year old cat. She is long haired and is normal weight. Every so often (2x a year) she will vomit, and I am not just talking about hairballs here, I mean full on vomiting until bile is present. After she vomits 5 - 10 times in one day she proceeds to hide and growl (which is uncommon for her) At this point we take her to the vet for her routine, which includes fluid injections, anti inflammatory shot, and anti nausea shot. She always gets a fever when this happens. My question is, does anybody else experience this, and if so do you have any solutions, maybe I am overreacting and this is common, but I have two other cats that have never thrown up, so I get very panicky because after all she is one of my babies. I have researched everything online about this and she doesn't seem to have symptoms of any particular disease.