Low morning cortisol but Dr. won't do ACTH stimulation test

I've just started going to a clinic that specializes in CFS/Fibromyalgia and I just got some blood work back that has me worried.

My morning serum (blood) cortisol was 5.5 ug/dL which he told me is way too low (normal is 6.2 - 19.4).  Other than that, I had low vitamin D levels of 15.3 ng/mL  (normal should be 32 - 100).  He recommended taking a homeopatic adrenal gland support supplement and a vitamin D supplement and left it at that.  

When I asked him if I should be looking into what is causing my low cortisol level, he just shrugged his shoulders and said "it didn't matter".  I wasn't very impressed with this answer as I have read that low cortisol can mean Addison's disease or even pituitary issues so further testing is required with an ACTH stimulation test to see if I have primary or secondary adrenal insufficiency.

Should I be pushing for this test or am I missing something here and am just being paranoid?  

Thanks :)

[rumpled]

I would find a conventional endo to run the tests. You do need to know the source as if you have a pituitary issue you need to know if you have any other issue, and if you have adrenal, you may need other medications such as florinef.

Make sure you get D3 if you go OTC (a doc would give you script D with a level that low!) and take a lot to get your levels up - and that will help you feel better too. Be sure to watch your bones as well as steroid replacement is an art and a science. You also need to know how to stress dose, have an emergency shot, get an emergency bracelet etc. This disease is life-threatening so you need to be prepared. I also suggest having anti-emitics on hand like zofran or phenergan.