From what you have mentioned, its almost 7 to 8 days over now. I can understand your worries.
There are lot of cause of vomiting
and loss of appetite,(mild to sever)
You should get him evaluated once for his complaint to get him examined physically by a pediatrician
If needed investigated him...I would advice:
keep him Hydrate. Is most important condition in illness
1.Give plenty of water(1/2 liter water+ 4 tsf sugar+ 1/2 tsf salt) Or ORS
2.Apple juice,Pomegranate juice, Coconut water, lemon water Butter milk, Rice Kanjee,
3. Proper hygiene.
4 Avoid out side food.
"I Wish He will Recover Soon "
Regards Dr. Sagar Mhatre