I know what I am going to write will sound strange to you and others, but.... as a RN, I have seen patients that have diarrhea have been found to be constipated. There is a hard stool in the colon that cannot move, and the softer bm is squished around it and then there is diarrhea. Could that be a hairball that is blocking her up?? A simple X-ray of the abdomen should show if there is a mass in the colon. Also, if your cat is has been vomiting and has diarrhea since LAST Thursday, she will become dehydrated and that does not help the situation. Please post after you see the vet tomorrow....Good luck!!