Why do I get bizarre cold sensations in profound Metta states?

At one point, when I attain a state of very profound calm in Metta, I tend to experience bizarre body feelings, such as chills down my spine or a sense of extreme coldness in my hands and feet. This is unsettling. I question whether this abrupt feeling of coldness is an indication of my nervous system expelling some underlying stress, or it is my nervous system surging up my nerves since my body is anxious about the shift in state. My name is Pranav, born on 12th December 1995. Time: 10:10 PM. Location: Kolkata.