Hi, My new 10 week old puppy is very lethargic. He hasn't eaten anything in about a day and drinks only a little water. I had him at the vet two days ago where she diagnosed him with an upset stomach and gave him IV fluid to rehydrate him. He was getting better yesterday morning then the symptoms returned along with not eating at all and vomiting twice. I am really concerned, but the earliest appointment I could get was tomorrow morning. I guess I'm wondering how worried should I be? Any ideas what it could be?