Thank you for your query,
Your child seems to have gastroenteritis
which may be due to a virus or protozoal like giardiasis
Maintain her hydration by giving sips of oral rehydration fluids like Pedialyte
Monitor her hydration by urine output, activity, skin turgor, and tongue moisture.
Stool to be sent for routine and for culture and sensitivity to know the organism.
The distended stomach is due to distended bowels which may occur in gastroenteritis or due to electrolyte abnormality.
Consult your Pediatrician
for the assessment and treatment.
Hope I have answered your query.