Help with blood labs?

Hi everyone,

I have no history of CFS except for when I was recovering from IBD. I was on prednisone for 4 months last year, and 5 months the year before. This year I haven't been on it at all, but I've been feeling very tired. My recovery on the whole from auto-immune has been good, but I have lingering fatigue.

My doctor referred me to an endo for some hormone testing and here are the results:
Testosterone 30 (upper normal is 28)
ACTH 13.6 (upper normal is 13.9)
AM Cortisol 435 (normal range 125-536)
Prolactin 13 (normal range 3.8 - 20.6)

My other blood work is all normal, including iron. I have no inflammation that comes in blood work. Effectively I'm in remission. But I'm so tired all the time. I don't know why the testosterone is so high. I don't workout that much and I don't have an active sex life. If anything my libido is kind of low.

The endo says that my high-normal ranges are because my adrenals are coming back online after prednisone use, and the ACTH is trying to trigger the adrenals into more activity.

I don't know enough to know if this is true or not. Could anyone shed some light? Are there other kinds of tests I could request to get a more accurate picture?

I'm so ignorant when it comes to the hormone system.