Hi, my 3 year old has a chest infection and started a antibiotic 3 days ago, but to me she is getting more unwell, her cough is horrible, is it normal?

Let explain: If she is not getting better take back to the doctor and have check her again, possibility do chest x-ray and may change her medication and nebulizer to the treatment.

Go to MD: If it is your instinct that your child is getting worse, i would take her to the doctor as soon as possible. Sometimes a chest infection can progress into pneumonia.