I would believe it does have to do with thyroid , if you have a nodule this can sometimes try to overwork for the whole gland and over produce thyroid hormone. I was also hypo for years , but suddenly couldnt sleep,heart startling while trying to go to sleep,could not eat (lost 45 pounds in 6 weeks) It was horrible. Now have had ntt 3 weeks ago and only time cant sleep is when synthroid dose is increased.
It may be too much medication -- would test TSH -- if low, decrease the dose.
To bbb444 - this would not likely be due to a thyroid nodule "intermittently" producing thyroid hormone