What Causes Episodes Of Fatigue And Uneasiness?

I am a 66 year old male who has had a complete adrenalectomy 50 years ago. In the last 2 weeks I have had on and off queasiness and fatigue which comes and goes. I can be feeling awful and then, in a manner of minutes, I'm fine. I take Cortef and am on blood pressure medicine and am under the continuing care of my family physician. I will be seeing her in a few days but was wondering if I could have a touch of something right now.