What Is The Recommended Treatment For My Child With Vomiting, Loose Stools, Fever, And Stomach Pain?

My son is 10 years & 6 months old . He vomitted after getting up today in the morning. Then went twice for motions , motions were loose but not proper . He had 100 fever after motions & complained of stomach pain. I though it was stomach upset. Administered him Ibugesic plus ( 10 ml ) , Flagyl ( 7 ml) & zifi 100( 7 ml) syrup. Fever came back after 6 hours & again gave him Meftal P which i had. I gave him above medicines from his doctors file which was his line of treatment 2 years back when he was 8 years old. Now we have shifted last year & dont have access to his doctor. i suspect it may be a viral infection. Given the present day scenario i need the line of treatment for him .He prefers tablets but i have given him all syrups.