dania, if your A1c is 7.0, you’re diabetic. That FBG of 8.6 mmol (155) confirms it. Did your doc not point that out or attribute that to your potential Cushing’s diagnosis? Do you remember how high your urinary cortisol was? When you said you increased carbs, I assumed that you may have been VLCing, like many people do when they mess up their hormone and immune homeostases. High DHEA-S is suggestive of adrenal dysfunction but if your ACTH and cortisol are also high, then you might have a real endocrine issue. Cushing’s frequently results in diabetes if untreated due to impaired insulin sensitivity. How’s your cognitive fucntion, blood pressure. Have abdominal obesity or any edema?
High cortisol could be due to a pituitary tumor but the most common reason is due to taking corticosteroid and immunosuppressive medications for autoimmune or other conditions. Did you take such drugs or other similar drugs? You’ll need a pituiatry MRI and possibly an adrenal scan.