The differences between a cold blooded creature and a warm blooded creature is that when something is cold blooded they're hot when it's hot out and cold when it's cold out and have no ability to control or regulate their body temperature and cannot generate body heat.
Warm blooded creatures such as Humans are hot when it's hot and cold when it's cold but the difference is that warm blooded creatures such as humans can regulate their body temperature and can generate heat from their bodies to stay warm such as by shivering.
When a person is shaking or shivering that's the way of the persons body trying to generate heat to stay warm.