Thanks everyone!! I feel soooo much better that he will survive the day!
I don't normally put a sweater or jacket on him unless I am home with him, because he has often had issues where his leg got stuck or it got twisted around, etc. and I worry leaving him in one. That's why I USUALLY leave the heat on for him. I was just totally unaware it would be this cold today!! Thanks for all the tips and for letting me know he should be fine. WHEW!! I knew good ole' Yorkie Talk would help me out!! Thanks everyone!!