Here are some posts that I made last year that I think would be helpful to review for basic info (and some in-depth info), if you don't already know your way around a Cushing's Diagnosis:
Symptoms of Cushing's
Types of Cushing's Syndrome
Distinguishing Cortisol Highs and Lows
Treatment for Cushing's
And there is a series of posts I made this month that goes through commonly-used tests starting with: "Testing for Cushing's, Introduction"
And, if you want to get a feel for what the struggle is like? Here's a monologue I wrote that was preformed readers-theater style locally: A Big, Fat Target