You really need to get him seen by a vet soon.Try to keep fluids in him as much as you can.You could try to get him to eat some rice and chicken broth.Has he been fully vaccinated or is there a chance that he might have gottne into something?Please let me know how he is doing.Good luck and May God Bless.
Your dog needs to see a vet asap, he could have an illness or something stuck in his throat, or teeth problems, or possibly swallowed something poisoness. . Is he still drinking water? If not, he won't last long, he'll become dehydrated fast.