Thanks WD and OM -

sleeping pad = Exped Synmat UL7. I had on wool baselayers, socks, and my windjacket, but my dog had claimed my puffy jacket for the night. Bag was Feathered Friends Vireo. I just found it odd that I didn't feel cold, given that I always feel cold, even sitting around at home at 60 degrees.

exhaustion: I usually don't sleep my first night away from home; that held true here.

dehydration: yes, truly sounds like the primary culprit. I have the in-one-end-out-the-other issue too. I hadn't had much luck against it using electrolyte replacements at home, but for something like this it might have helped. I may also go back to using a bladder system. It's a pain wrestling the reservoir in and out of the pack for refills, but I can't wrangle a water bottle and hiking pole and leash with just two hands.