Thanks for your query.
Your child is having diarrhea
which is most likely antibiotic associated and will settle after yoy stop antibiotic.
Loss of appetite is a part of illness.
Give her oral rehydration solution sip by sip after each loose stool
,give coconut water,vegetable soup.
Give solids only when appetite improves.
Give lactobaccilus sachet for 2 to 3 days.
Continue with medication as advised.
Wishing your baby good health.