Adelle,
This is an area that's always been of interest to me and as Michelle pointed out, it's an adrenal issue in my opinion.
Both sudden stressors and chronic (ongoing) ones can tax the adrenals more-so in people with autoimmune diseases, especially endocrine ones like thyroid. It's similar to the state experienced by people with Post Traumatic Stress Disorder and research studies on PTSD state that the stressed adrenals are what causes its symptoms. I refer to it as "adrenal fatigue" because it's a good term for a subclinical type of lowered adrenal function.
When I first experienced noticable symptoms from Hashimoto's-hypothyroidism, I was in property management at the time (stressful)and with delay in treatment due to doctors not ordering proper tests to diagnose me, I developed co-morbid (co-existing) adrenal fatigue. I still experience spells of it that can at times be severe with severe stress or if I exceed my tolerance level physically. I have Chronic Fatigue Syndrome as well and even with optimal thyroid hormone replacement, it has to be treated as a seperate issue because of symptom flares.
Another reason adrenals are fatigued more with autoimmune diseases is because they are inflammatory and there's more demand for the adrenal hormone "cortisol", the one that is most often low with adrenal fatigue. Cortisol works as the body's natural anti-inflammatory and constant demand for it can cause it to go low at times.
Here are a couple of interesting research study quotes:
"CONCLUSIONS: The results of this pilot study indicate that low-dose cortisol treatment reduces the cardinal symptoms of PTSD."http://ajp.psychiatryonline.org/cgi/content/abstract/161/8/1488"Dr. Reeves said: "People with CFS have reduced overall cortisol output within the first hour after they wake up in the morning, which is actually one of the most stressful times for the body."http://www.ei-resource.org/news/chronic-...ortisol-levels/I'm quoting these to show the relationship of low cortisol to conditions that have adrenal fatigue as a feature of them. As far as supplementing with cortisol to help with it, other studies recommend against it. There are however safe supplements that can help and I talk about these in this article>
http://www.bellaonline.com/articles/art37137.aspIn your case, extra rest and reducing stress for a while might be enough to get your adrenal reserves at better level. If you do struggle with it, you might consider adrenal support supplements that your doctor approves. Also if you have any suspicion that your thyroid levels are a little low, you might ask your doctor to order a blood recheck to make sure your thyroid hormone dose is high enough. I believe it doesn't hurt when you struggle with fatigue, to have thorough blood work done, just to make sure you don't have developing anemia, etc...
I'm pretty detailed in replying on the forum but that's because traffic is not high, so gives me op to give detailed replies.
I hope this info helped.