If your pet has had recent exposure to extreme cold, experiencing weakness, lethargy, or low body temperature, they could be experiencing hypothermia. Wrap your pet in a towel or blanket to transport to a vet. Your pet may be experiencing circulatory failure if it has not been exposed to the cold, but is experiencing low body temperature. In this case don't try to actively warm it, for this may do more harm than good. This is an emergency situation and your pet should be transported to the nearest veterinary facility.