What is it like to have addisons disease? what are the symptoms? will it affect a person's day to day activities?

Depends: The symptoms depend on the length of the disease and on how low are the hormone levels. Usually, untreated, this condition is severe and can cause low blood pressure, lethargy, unconsciousness, low sodium, high potassium and low blood sugar - adrenal crisis. Earlier symptoms are inability to cope with sickness, weight loss, salt craving, sometimes darkening of skin.