A lot of patients with thyroid disease also have some co-existing adrenal fatigue and in fact we have been discussing this on some of the past Thyroid Health forum threads.
Add to thyroid disease, something like a traumatic or very stressful even and you can really suffer from adrenal fatigue. Your circadian rhythms are off with this condition and is why your sleep patterns are disrupted. Your cortisol and DHEA will have their peaks, at the wrong times, such as at sleep time and your normal drop in these hormones also happens at the wrong time, like during the day, when you most need the peak energy. Adrenal fatigue that goes on for a long time (chronic), then becomes "adrenal exhaustion" and this is the point to where you no longer experience those needed peak levels at all.
I have had adrenal fatigue for several years, as a feature of Chronic Fatigue Syndrome and have also experienced adrenal exhaustion. Mine turned into adrenal exhaustion, after experiencing the onset of Hashimoto's/hypothyroidism and at the same time, I had gone through a terribly stressful period of time.
Mine did not improve when I first began thyroid hormone replacement but actually worsened for a time. After several months on the correct thyroid dose, I finally saw some improvement in thyroid and adrenal symptoms. At times of extra stress and extended periods of hard physical activity, I've taken some adrenal support supplements, that I learned about when researching about adrenal fatigue and these have helped. These included multi "B" vitamins, especially B-12, in sublingual form (liquid) and vitamin "C", magnesium, selenium, zinc, DHEA 25mg (over-the-counter adrenal hormone) and sometimes but less often, an Adrenal Cortex Extract (processed beef adrenal glands in pill form).
These always help me greatly but I don't take the ones containing actual adrenal hormone (cortisol), as a permanent regimen. As safe as they are supposed to be at the recommended doses, it likely would not hurt for me to do so if I felt it was necessary.
I considered taking a cortisol drug called "Cortef" (natural adrenal steroid) and had a Dr. willing to treat me with it but I was a little wary of steroids and I still am. I have however, read many reputable medical resources that state that Cortef is safe as physiological doses (25mg and less), to supplement a person's low cortisol levels from adrenal exhaustion but can cause "adrenal suppression", if administered in full replacement doses (above 25mg but may vary) and if used for extended periods. In my opinion, adrenal support supplements are safer and usually all that is needed for most cases of adrenal fatigue.
How does a patient know if they have adrenal fatigue? Blood adrenal hormone levels can be helpful but are like a "snapshot reading" and since cortisol levels go up when you are stressed, like at a blood draw, this can affect the snapshot blood level.
This is why saliva testing is recommended because you can conveniently get several cortisol-level readings over a 24 hour period to establish the adrenal hormone rhythms.
Saliva testing has been researched and found very accurate, in fact it is used to monitor hormone levels in medical research, including that done by the World Health Organization. It is also an approved form of testing, by many major health insurance companies, such as Blue Cross/Blue Shield.
Many pharmacies carry the type manufactured by "ZRT Labs, Inc.", which is also an approved blood lab, so you might check with your pharmacy to see if they carry this brand.
Most adrenal saliva tests are not expensive and can be diagnostic in detecting adrenal fatigue.