Addison disease??

Anyone on here been tested or diagnosed with Addison's disease please let me know. My 7 year old daughter has suffered with low blood sugars since she was about 9 months old with episodes happening happening from once a month to nothing for 3 months. Now doctors are finally taking me seriously she had some blood tests done 2 weeks ago and her cortisol levels came back low so I was told she will need a synacthen test I google the cortisol levels and synacthen test and it brought up Addison's disease she does have a few symptoms of Addison's disease low blood sugars been one of them. Can anyone give me information on what the test includes and if it's diagnosed what will her life be like??