Adrenal adenoma

Hello, I was told that I have a 1.8cm adrenal adenoma in May 2009. After my own research I asked my doctor if she would check my hormone levels. She checked my acth, dhea, prolactin and testosterone.  Everything came back within the normal range.  My ACTH was 8 (morning draw) and the range says <46pg/mL. I was on birth control at the time of the draw.  After yet more research on my part I questioned this result as well.  My doctor said I should only worry if it's high.  

My thoughts are:
Cortisol should have been checked when ACTH was checked
If morning levels are highest, why was mine so low?
With no bottom range, how do you know what's too low?

I have several symptoms...nothing to worrisome, but annoying.  I finally got my internal medicine dr. to entertain my thoughts, but all he did was order another ct scan which I did today. If anyone can help me better understand what I should push my doctor to do from here, I would greatly appreciate it. Thank you.  

[Firefly234]

I would recommend seeing and Endocrinologist. Find one who specializes in adenomas (not all do). Generally, the range on the ACTH test is around 7-50 pg/ml, but each lab is different. The test is usually run with the cortisol test at around 8 am. I have secondary adrenal insufficiency, so I don't have any ACTH. My ACTH tests come back at <5 pg/ml. Your doctor probably reran the CT scan to see if your ademona was growing substantially. However, you should get your bloodwork done by a specialist, not a PCP/GP. These tests can be complicated and difficult to interpret. Your doctor may be great, but he's not trained in that field of study.

[adenoma]

Thank you for the advice.  I live about 2 hours away from the nearest endocrinologist, so I was hoping to get help without the long drive. Can I ask what your symptoms are with secondary adrenal insufficiency?  I told this doctor that I am not worried about malignancy. I don't think it would have grown much since it is so small anyway.