Hello, I recommend that you try to find a veterinary emergency center near you as these places are open on the weekends and holidays. If one is not available near you then I would not offer your dog any food for 24 hours. The process of digestion could further irritate his stomach and intestine, sometimes just the smell of food can make them nauseous. As long as he can keep down water, continue to give that to him at will. If he is able to take in small amounts of soft food then you can give him over the counter Pepcid at 1/4 of a mg per pound. So if he is 10 pounds he can have 2.5 mg or 1/4 of a 10 mg tablet every 12 hours. This is the only thing I would give by mouth until tomorrow.
Then reintroduce food slowly. Typically as a bland diet consisting of cooked plain rice or noodles mixed with canned or all white meat chicken in a 4:1 ratio of rice:chicken. Feed just a tablespoon or so at first then every 4 hours or so, offer a little more until he is eating well again. Then you can start reintroducing his regular dog food in a day or so. Thanks for your question.
J Bache, DVM