Baby 6month having diarhoea

My baby 6 months having diarhoea for 6days now. Pls help what should i do to stop his diarhoea? I go doctor and he say maybe infection. Doctor pescribe me prebiotic Lacto GG but still the same my baby got diarhoea. But as a mum im not sure until when will i need to wait for the virus to go away. Or should i change his formula milk? Currently his drinking brand grow from newborn til now. Even he feed well still can drink But he will poop bit by bit after fed. A bit watery yellowish. So need tp keep changing his diaper often per day. Pls help me mummy what u all suggest for me.#advicepls #pleasehelp #firsttimemom