Odd first meditation experience...

[lnfinite]

Would love some of the members on this forum's insight. Thanks

During my meditation session today i was using the "do nothing" technique and i began looking at the TV's red light in front of me while it was turned off. I was also doing a strong determination sit as well not moving whatsoever. About 10 minutes in i started to feel a weird thump on the back of my skull i felt it because my head was against a wall. It just started bumping and moving on it's own as if a caterpillar was crawling in there moving around. I lost feeling in my body and my awareness was only identified to my skull as i became conscious of this i felt a tremendous amount of fear and my heart beated at almost triple the rate it would on average. I have no disabilities or breathing problems. While this was happening, i didn't feel an experience of nothingness or absolute at all but was this a reaction of the ego knowing it would have eventually been reached if i had kept going? Because i had to stop my session as it was gradually increasing my heart rate and made me anticipate an oncoming heart attack. seriously. Anyone experience such a thing? Would love to hear from some of you.