My little boy has been throwing up for a week straight now, an cannot hold anything down in his stomach! Started last thursday, getting sick at least 4 times a day, can't keep anything in his belly, not in mood to eat, fever comes an goes, been to 2 hospi

Hydrate, see MD. Time to call the professionals. Make sure he is adequately hydrated.
You . You need to take him back immediately to the er. It sounds like you have been doing all of the right things and getting him checked, and it sounds like it has been frustrating, but as he cannot hold anything down he must be reevaluated immediately so that he doesn't become dehydrated. Please take him immediately back to the er.