I phoned my doctor for an prescription for clarithromycin because my chest is really bad my skin is really pale could you tell me why?

Pneumonia. Especially mycoplasmal, can be associated with an anemia. You should have your blood count checked.
Not a good idea. It is not a good idea to take antibiotics for something like your symptoms without knowing what you are treating for.I will recommend to make an appointment and let doctor decide what is your diagnosis and what treatment you need if any.