It's when you're totally exhausted and you're lying in bed trying to fall asleep but you're suffering from a bout of insomnia and you want to fall asleep more than anything and you don't realize it but you actually are asleep, having a nightmare about experiencing insomnia.
I've had insomnia ever since I was a boy, but it's really awful when it follows you into your dreams.
And how do I know I was dreaming and not just lying awake, trying to fall asleep?
Well, it's either that or I suddenly teleported from an alternate universe where I was sleeping in Alternate Arkansas in one of the bunk beds my brother and I had when we were boys, even though we never had them in the configuration that was in the "dream" about trying to fall asleep.
This has to be the worst kind of nightmare. Being chased by an axe murderer? No sweat. Being naked in public? No problem. Realizing you haven't been to a class in college all semester and now it's finals time? I can deal.
But dreaming about not being able to fall asleep?
So what's your worst nightmare?