You said you were diagnosed with overactive thyroid, then normal, then underactive... were you diagnosed with Hashimoto's and are you on replacement thyroid hormones?
What are your current Free T4 and Free T3 levels, with reference ranges? Even though I suffered from terrible exhaustion, I didn't sleep for more than a couple hours/night when I was hypo either. Once my levels got where I needed them to be, I could sleep normally. My endo recently decreased my hormone dosage and my levels are no longer where I need them to be; I'm only sleeping a few hours/night and can't get through the day without a nap. I'm retired, so I have the liberty of doing that; I can only imagine what it would be like having to work 13 hrs/day.
If you'll post your levels, we'll try to help you through this.
In addition, I had similar symptoms when my B-12 levels were too low...
I have insomnia when magnesium levels are low (happened just recently actually..due asthma medication this time) and hyperthyroidism.