See
http://diagnostechs.com/ for their info on the ASI (since it is their test).
This is something that can be fixed and likely prevented in the future, assuming you heed the warning signs.
Corticosteroids (oral) will not fix the problem, they will only cover the symptom of low cortisol.
Resting alone takes a long time to fix a problem of this nature. Giving the body the nutrients that have been depleted, along with adjusting your training, is the answer. I do this quite a bit with patients (who have this issue).