I can't tell you how many kids I've nursed through hell and back .. mine, neighbors, grandkids etc etc
It sounds like a virus and you do NOT take medications for virus' ... unless there is fever involved, then you simply use a fever reducer.
You need to keep a vomiting childs electrolites up. There is a liquid called Pedialite that is 1000 times more effective than gatorade for that. It was created exactly for that reason and is sold over the counter, usually in the babyfood or formula isles. This is absolutely the best thing you can give him!!
If he doesn't want to drink, look for the Pedialite popsicles in the freezer section, if you don't have those regular popsicles will do. The object is to keep him hydrated.
Food for a couple of days is NOT necessary but chicken broth, jello, jello water (this also helps with loose bowls), rice water, and flat ginger ale or sprite help too.
Its the hardest thing in the world for a parent to see their babies sick but I'm certain he will be fine
*hugs*