Thanks for this idea. I have been tested before for my blood sugar response or whatever that test is but it's a test that they do first thing in the morning after fasting and it usually happens on days when I feel fine so they rule it out.
Maybe I will buy my own blood sugar monitoring tool and try to keep track on an ongoing basis over a month.
It could be the effects of hypoglycemia which may cause the fluctuating/intermittent symptoms.
Low thyroid function can cause hypoglycemia because:
it slows the rate of glucose uptake, decreases rate of glucose absorption,
slows response of insulin & slows the clearance of insulin from the blood circulation.
Look into a low carb low glycemic diet and spread your your food intake over more frequent & smaller meals.
Untreated or undertreated hypothyroidism may be a precursor to Lupus, Sjogren's and other serious diseases.
Hope this helps,
Niko