My dog has been vomiting for 3 days now and I just gave him Cephalexin but I have a medicine called Metociopramide which my vet said is for vomiting but I am not sure if I should give him that also. My dog has not eaten anything different and for the last 3 days he has not eaten anything at all. Nothing is coming up in his vomit except a water substance there is no blood or food so I am not sure what to do