Should Antibiotics Be Given To A Child For Loose Motions?

hi my daughter is 26 months and she got viral motions since yesertday dr advised to give sporlac and sd this will continue for 3- 4 days today she asked to start with antibiotice OFM 4 ml twice a day for 3 days her weight is 10.5kg last week she was hospitalised as she had cold and cough and her medication got over on sunday i m worried that so much intake of antibiotics wld impact her . her weight was 11.800 before getting admitted in hospital. my daughter is THAL MINOR her hb is 9.3 she is not eating food i m forcefully giving her ORS and water. can u pls advise if antibiotics is going to impact her and how much time will it take for motions to stop.