Hi, I got my Yorkie 4 days ago. When I got him, he was healthy and active but all of a sudden he got lethargic and he can barely walk. He does not want to eat but he drinks water. I brought him to the vet awhile ago and the vet prescribed antibiotics and vitamins and some water-soluble glucose. After a while he started eating again (He ate the a/d prescription dog food) and he started drinking water. I have noticed that his stool is kinda watery. Is it because of the change in diet? He can also walk already but he isn't that active yet. What seems to be the problem? I'm worried

Its already 6AM here in our country and I can't sleep because I am too worried about my baby. I hope I can make him feel better

Thank you.