Literally banging my head against the wall

I am working on a project that is more challenging than most; I like the challenge, but the time frame is making me crazy. I hit the wall this afternoon, staring blankly at my computer screen. I just... didn't... want... to... think. I got up from my desk and grabbed something from a lower bookshelf and promptly cracked my head on some built-in shelves above. It's amazing, actually, that I've not cracked my head on these before.

It was hard enough that I immediately checked for blood. No blood but a nice bump and a bit of a headache.

Time to call it a day.

I should have worked tonight, but I didn't have it in me. Tomorrow I seriously need to buckle down.