for the first time ever I am cold this week too. But don't sit there with your coat on. Stick an exercise DVD on and do that - I find 5 mins of doing the shred DVD and not only am I knackered but glowing nice and warm. Failing that do 50 star jumps or 50 steps up and down on the bottom stair - that'll warm you up. Or have a really hot bath and then wrap up warm.
Hope you feel warmer soon - says she sitting typing with blocks of ice instead of fingers ;-)