I don't know how old your son is or what he has been through but if he can't even keep liquids down dehydration could be a serious problem. An easy way to check is by lightly pinching the skin on the back of his hand. If it automatically flatens back down then he isn't dehydrated. If the skin stays peaked from the light pinch then he is dehydrated and that is extremely dangerous in babies. I had a nurse tell me how to do this. You can do it to yourself to see the difference as well. My doctor has also told me before that a baby should be having at least 3 wet diapers a day even when sick.

Don't underestimate your mothers instict and don't hesitate going to a different doctor if you aren't confidant in the one you have. Just because someone made it through medical school doesn't mean they're any good.

Hope everythinggets better. Who knows maye the antibiotic will get whatever is wrong.