Welcome to HCM.
It is nice to know that your son has been de-wormed. Since he is vomiting and toilet frequency has increased, make sure he is well hydrated, give him re-hydrating fluids orally and soups to maintain the electrolyte content of the body system.
Make sure he is not eating any contaminated food, that may cause gastroenteritis
like symptoms. Consult a paediatrician and get all LFT, liver function tests done to rule out any liver ailment, food poisoning
or acute gastritis
. Stool test
( routine and culture ) should be done.
Get him admitted in a hospital to avoid dehydration
and worsening of the condition. Antiemetics, antacids can give him temporary relief. He may need injections and infusions for better recovery. Take care.