due to the very low calorie intake your body actually lowers your core body temperature by a degree or 2 to save energy ( like if you didnt have much gas you would turn your heating down a bit ..) , hence the cold feeling we all get !!
You have my sympathy - been absolutely frozen since I got home. Had a coffee & sat huddled up under a blanket on the sofa. Going to drag myself onto the Wii fit in a few minutes to try and warm myself up then have a hot shower. Shame I'm dieting really - I'd be able to make amazing pastry with my hands this cold!