I have been doing meditation for last one year regularly before going to bed at night. Recently I have started feeling some sort of electric current passing through my body, especially in my spine. During the sessions, I feel intense rays of heat which move in circles on my forehead. For the last few days the intensity of such currents and sensation has increased tremendously, through out the day. Though I am enjoying it but still there is some fear. Please guide me what exactly is happening?