My body is like a furnace

Today, after finishing a tough 20 mile run, I started shivering and couldn't stop (this is a semi-normal experience after tough workouts). The ice bath afterward didn't help. Now, several hours and several slices of pizza later, I am feeling pretty hot, even though my window is open to 59 degree weather. Seriously, it's like I am a furnace. I burned all my fuel and my fire was out. Then I restocked it with pizza, and half a gallon of milk, and its burning too hot. Strange but fascinating.