Usually antibiotics would require at least 2 days to take effect and reduce symptoms, only if the infection is bacterial. They have no role in viral infections. Kindly get her stool examination done, if you haven't already.
Also if the fever continues, you would also need to get a blood test done
Next Steps
in the meanwhile, try and maintain hydration with ORS coconut water, glucose water, lemon juice, rice kanji, buttermilk and/or curd