Q. My cat vomiting 3 times after that she does not want to eat anymore and seems to get weak
DAVID ELBEZE, DVM, MRCVS
A. If your cat vomited 3 times already and is getting weaker - she must suffer from a gastrointestinal condition. it could be an infection if you are lucky, but it could be something much worst such as a foreign body obstruction the intestines, renal failure or pancreatitis. it could also be a tumor in the intestines.
I strongly advise taking her to the vet today in order to diagnose the problem and treat it.