Hello girls! Could you please tell me what to do in such a situation? ...

Hello girls! Could you please tell me what to do in such a situation? My little one is about three months old, and there have been problems with her tummy. She often starts vomiting and has become more frequent bowel movements. There's mucus and white lumps in the stool, and she makes a gurgling sound in her belly frequently. I went to see a doctor, and it seems like lactose intolerance, so they prescribed Lactazar and Linelx Baby, but it hasn't helped after a week. I tried a lactose-free formula, but the vomiting stopped, but the bowel issues remain. I don't know what to do next...