What Should I Do About My Infant S Diarrhea, Vomiting, And Drowsiness After Antibiotics?

Hi. My baby girl is 6months old. We had a flu vaccine 2 days ago since then she had a temperature and diarrheas (motions 8-10 times a day). Now the temperature is fine but still suffering from diarrhea due to this she got an severe diaper rash so consulted a doctor and they have given cefixime & ofloxacin since started using this she was not having milk properly and vomiting s also started. today she was not active and drowsy too... Please suggest what to do and also what to use for diaper rashes.