Thanks for posting your query.
With the available described symptoms, there appears to be possibility of acute gastroenteritis; most likely viral in origin.
Presence of diarrhea
along with weakness suggests the diagnosis.
You should consult with internal medicine specialist and should go for thorough check up.
You should take complete antibiotic course, probiotics and antispasmodics.
Weakness is due to loss of potassium in watery diarrhea.
You should also take potassium supplements such as banana, lemon water, juice and coconut water.
You should maintain your hydration.
Dr. Mayank Bhargava