Do you ever get your head so full of random ideas, things-to-do, miscellaneous thoughts that you can't get anything done?

Man, I'm on a serious deadline here. I need to read two book chapters and complete an assignment for the online course I'm taking and I have to have it done in a few hours... But I just can't THINK!

Yeah, I'm procrastinating here... <sigh> But unplugging the PC/Internet wouldn't help though because it won't unplug all the stuff that's going on in my brain -- which doesn't need a plugin or a net connection. It's happy just to keep distracting me regardless.

I don't think I'm ADD or anything but... I just... can't.... concentrate...

Any suggestions??