Levoxyl and mg dosage

I started taking Levothyroxine about a year ago. A couple of weeks ago, I started to have problems sleeping. I would fall asleep just fine, but I would wake up in the middle of the night or an hour or two before I would have to get up and would be unable to go back to sleep, even on days where my stress was minimal or not enough to get me anxious around bedtime. It would seem strange that the side effects would start so late into the therapy, but sometimes long-term usage of a drug can cause side effects. I went to the doctor for my yearly physical in January, and my blood test results showed that my thyroid levels were normal. Has anyone else experienced this problem? Please contact me if so. I'm trying to figure out the cause of my insomnia, and it would be great if I could either eliminate this medication as the cause or contact my doctor with information about sleep problems that others have had while using this drug. I believe I'm on the .025 mg dosage. Thanks in advance for any assistance you can provide.