hi brittanyclodfelter ,
I Have read your Question,
is a case where generally doctors prescribe a medicine known as sodium valproate
(since you have not mentioned the drug prescribed , Iam assuming it could be sodium valproate), The medicine is suitable for everyone and it could show a few side effects like , diarrhea
, aggression and behvioural changes as you mentioned above,
but sometimes empty stomach , the constant vomiting could also be the reason for irritation as you stated.
My suggestion is to consult your Physician or neurologist
immediately for the further advice.
Wishing your son a good health,