Thanks for your query.
Your baby is having acute gastroenteritis
which is mostly viral in origin.and takes few days to settle.
I personally feel you need not to give two antibiotics for this.
Most important thing is to maintain proper hydration.so give oral rehydration solution sip by sip after each loose stool
,give water,coconut water,continue feeding as you were giving before illness.
Continue with sporlac
for 2 to 3 days.
Wishing your baby good health.