Hi Doctor ! My Son Age Is 22 Months, I

Hi Doctor ! My son age is 22 months, i consult doctor as my child fell down from bed after dinner after 20 minute vomiting done again after 1 hour vomiting done, he was playing well and no any head injury even though we approached to doctor and following medicines taken PARACETAMOL 125 MGSUPPOSITORIES.
After that again vomiting done and started loose motions, again visted to hospital and stool sample given, doctor suggested the following medicines Adol 120mg syrup, kinderlove multi vitamin powder and electrolyte, but motions not stopped. Again visited hospital all stools result came negative no rota virus, no semolina virus, again doctor suggested kaptin and hexbio granules, now stool is not fully loose moderate but daily three time motion in mild green and yellow color. Found some sound in stomach after taking hexbio granules, total 6 days over. doctor said nothing serious and 300ml syline injected, blood test done and told everything is ok. My question is why loose motions started? why motions not controlled ? Is there any serious ? now we are using kaptin 4 times a day and daily 1 packet hexbio granules? is there any serious issue? Please advice.