Sleeping outside near campfire

This happened a second time, going to sleep near a campfire with plenty of time on the fire to spare and woke up freezing with no fire. This time I've made a fire, cooked something and it was 1:45 left, so I said, let's rest for 1:00 hour. Of course I've woke up almost dead. Before this, I've put Fir wood on a fire for 9 hours and went to sleep for 8. Woke up freezing. What gives?