I heard lots of people say they were cold.
It happens occasionally to me.
I keep wondering if I'm eating enough fat or protein that day.
Today is bad.
My breakfast was spoiled on the way to work (I carry it in a container and nuke it once I've arrived). It spilled all over my backpack.
Anyway, I ended up mixing up a shake (happened to have a package that my hubby had purchased for me - just coincidental).

So, I haven't eaten anything substantial today, and I'm finding I'm cold. My fingers and toes are really like ice today. I still think my original theory is valid - I haven't eaten anything to burn off, creating heat.

Other times, I'm fine. Other "cold" triggers are hunger or tiredness, for me. I notice it both times. So, perhaps it's more my body talking to me, than the real temperature outside my clothes.