I have just notice that i rock back and forth unconsciously?

I was just sitting cross legged while on my laptop and a saw my quilt moving ever so slightly as i felt myself rocking to the rate of my pulse! It was so weird, but it is very slight and hardly noticeable. I knew i was because i dropped a single hair over my eye and watched how it moved over a distant object to get a clearer view of the movement, it was definitely there. Is this normal? Do i have anything to worry about?