My 8 Month Old Son Has Been Having Diarrhoea Since

My 8 month old son has been having diarrhoea since a week. Frequency has gone down but stools still pasty. He had conjunctivitis before and later diarrhoea started. Gave him bactrim upon doctors advice. He passed his stool normally in the morning but later passed watery stools with mucus. Is this normal? Can I continue with the medicine? Except for this he is eating well and active.