Extreme cold feeling around head when I woke up?

This only happened once. It was last night, actually, but it was so bizarre.

I was having a nightmare, nothing abnormal. When I died in the dream, however, I had a transition from sleep to alertness like no other. It felt slow but fast at the same time, my vision was coming to me slowly, and there was a cold feeling around my head that I've never felt before. Despite never feeling the cold before, it felt like it was trying to pull me into it a second time, trying to be inviting. It felt so welcoming, it felt like it was trying to pull me into it and make me part of it. It felt familiar, and I almost wanted to accept the invitations it seemed to be sending to me. (Probably would have if I wasn't waking up in such a weird way.) When I fully woke up, the feeling lingered slight, but it was no longer cold. Then it was gone, and I was left feeling more alert and awake than I have in weeks.

I don't do drugs, drink, etc. Anybody think they can tell me what happened?

(Sorry if the Other Science category is not the place to put this, I have no idea what category this falls under, though.)

Extreme cold feeling around head when I woke up?