I woke up thinking "oh, shit, I'm coming down with a cold again?", but now I'm feeling fine. I think maybe I'm allergic to my hand lotion or something, since I woke up with a full-blown sinus headache with fun side effects, and it's all gone now without help from Sudafed or even herbal tea.
(Not that I mind it being gone -- I just can't figure out why it is, and how I could duplicate the feat some other time...)
It might just be stress. I do have a little too much of that, after all. And for once, coffee is actually helping me wake up.