My cat is 5 1/2 years old. Over the last several days, she has been vomiting 4 times a day. Her food has not changed, though we did change the brand of litter last week. The vomit is mostly watery with few signs of food digested. In addition, she is slightly overweight since she is an indoor cat. She also has a strange habit of not enjoying her food if the kibbles are crumbs. Should we be very concerned and take her to a vet immediately?

