My kid has pneumonia she's taken all the meds but isn't getting better, what should I do now?

My daughter has had croup, bronchitis six times, broncholitis 2 times and now has pneumonia. She's only 3. The doctors keep prescribe her medication, but it keeps coming back and every time it's worse. I've already changed doctors. I'm scared that permanent damage may be done. What do I do now?