I went to bed feeling perfectly fine and began feeling achy and cold. I am normally pretty warm. Very quickly it went from subtle to freezing and teeth chattering/shivering violently. I took 3 Aleve for the ache and took my temperature, thinking it was a fever, and my temperature was normal. My teeth chattered and I shivered violently for about an hour though I put on fleece and was burried under 4 down comforters and my husband spooning me. It gradually subsided...including the aches and after 2 hours I went back to my usual body feeling comfortable/warm. I woke up sleepy from only 4 hours sleep but I am otherwise fine.