Are you experiencing an elevated state of any of your emotions? For example more anxious or irritable than usual? Also changes in the temperature and weather can be accountable to our sleep routines.

I too am early to bed (9pm) and have been experiencing mid night time waking up lately. I blame it on the rise in heat and humidity. Interestingly, I have been diagnosed with sleep apnea. I sleep much better now that I have a cpap machine but it hasn't prevented the middle of the night wake up.

What do you do when this happens? I have to physically get out of bed. It really matters not how long I am up and around for I just need to get up. Generally I am near instantly asleep again.