Anesthesia does weird things to some of us critters. I, for example, need a nap after any dentist appointment that uses novacaine, and whatever they gave me - I don't remember what it was - for general anesthesia for the brain surgery I had made me shiver - I was convinced the room was freezing cold despite three blankets, and the nurse, who was comfortable in short sleeves, explained that was just a minor side effect some people experience!