I am really concerned that your kid is suffering from nausea
. Nausea (sensation to vomit) can be due to psychological and physical reasons. Nausea can be due to problems in brain, stomach, liver, pancreas
, upper intestine. Since the problem is for last 3 weeks, he needs thorough evaluation by a good pediatrician
is not going to help. Since the causes of nausea are many, treatment suggestions are unlikely to help without making a diagnosis.
Don't worry he is going to be well. Take care.