That middle layer of ick

I sleep really well at night, and I have great dreams. Dreaming is something of a sport to me, I can have a lot of fun there. My waking moments are fun, too. My life is joyful and satisfying.

But sometimes I'll be cozy in my lovely bed, drifting off happily into la-la land, and suddenly some scene of tragedy is playing out before me. A refugee camp. Or an accident scene. Occasionally, when waking up from a perfectly nice sleep, I'll find myself in the midst of swirling thoughts. Worries about loved ones or even just acquaintances from the web.

Has this happened to you?

What the hell is that, anyway?