Just got back from the doc. Turns out I've had a migraine. That would explain the fogginess, the piercing and throbbing pain in my head, the sensitivity to light and sound, the nausea. Not to mention the overwhelming urge to stay far, far away from the computer.
That would also explain why I couldn't form a lucid thought - never mind write a blog post.
Ok, so now that I know what's wrong and I'm confident that I'm not having a brain aneurysm, I'm going to take some funky pain relief and go to bed.