9 month old puppy vomiting, wont eat, and lethargic. HELP!?

Hello, I have a 9 month old pit mix pup and he is about 77 lbs. In the last 24 hours he has vomited yellow bile about 9 times. He wont eat or drink water, and if he does drink its the smallest amount then he throws up. He is very lethargic and just wants to sleep all the time. I had him at the vet all day today for them to monitor him then I brought him home so I could keep an eye on him and if his condition worsens then I will be taking him to the Emergency Vet. If he had stayed at the vet overnight he would have been by himself all night and I want to make sure he has help if he needs it... They said he was not running a fever and they didn't seem to be too concerned with his condition. They watched him all day and checked him over. He is home now and he is so sick. I don't know what to do to help him feel better. Has anyone had something like this happen to their pup or does someone have any suggestions as to how to get him do drink? I saw someone wrote somewhere they gave their pup low sodium chicken broth?...... He has had all his vaccinations and I feed him natural balance dog food and he always gets natural bones that wont chip off in big pieces, very healthy stuff. Someone please help me make my boy feel better. :/