Hi My Son Is 4 Years Old And He Has

Hi my son is 4 years old and he has been throwing up at night only once or twice. It started last Tuesday. Wednesday, Thursday ,and Friday night he didn't throw up. Sat and tonight he did. He has not eaten much since last Tuesday but he does drink fluid. During the day he seems fine . He plays but he has been real clingy to me.( I'm the mommy) he wants to be held and he wants me to hold him all the time. And that's not like him. On a normal day he will want to be held a few times. So I'm not sure what is going on oh and he is not running a fever