Thanks for posting your query.
With the available described details, there appears to high possibility of Acute viral gastroenteritis
You should consult with internal medicine specialist/ gastroenterologist and should go for thorough check up.
He should go for complete blood count
, erythrocyte sedimentation rate
imaging, and serum electrolytes, renal function test.
You should take complete antibiotic therapy, antispasmodics, probiotics, antipyretics, if needed.
Frequent watery diarrhea and vomiting may cause weakness due to loss potassium.
You should maintain your hydration status by taking potassium rich liquids.
Take soft diet
along with yogurt and banana.
Avoid milk and all milk related products.
Dr. Mayank Bhargava