Thanks for posting your query.
With the available described details, there could also be possibility of partially controlled acute viral gastroenteritis
You should consult with internal medicine specialist/ gastroenterologist and should go for thorough check up.
You should also go for complete blood count
imaging, and serum electrolytes, renal function test.
You should take complete antibiotic therapy, antispasmodics, probiotics, antipyretics, if needed.
You should maintain your hydration status by taking potassium rich liquids.
Weakness is due to loss of potassium in watery stools
Take soft diet
along with yogurt and banana.
Avoid milk and all milk related products.
Dr. Mayank Bhargava