SOS meditation out of control ???

[songs of dreams]

Hello everybody,
I am in need of help with meditations specifically post meditation awareness. I just started this form of meditation (visualizing inhale exhale and breath control along with a repetitive suggestion in the mental background). I allow the repetitive suggestion to become mentally automatic in the background with my main focus on visualization of breathing. This puts me into a very deep void where there is no time or place, but a cradle of comfort. Several days later I experienced a panic attack response because I did not know what was happening. A very powerful energy stimulus emanating from behind my heart or my spinal back, almost like a storm and rising up above my head uncontrollable. I can only explain it as compared to my back having an orgasm of energies being expelled out and up. This has frighten me considerably, since then I have refrained from this form of meditation, but lately I was compelled to do it again. As expected the energy expulsion occurred again when I was outside the following day and has occurred several time after each meditation session. Please someone WHAT IS HAPPENING and should I stop, naturally the subsequent attacks or relief of energies are not as scary but they still exist with great force. HELP