Shaking REM and movement i Wanted to know what kind of experience i had today while i meditated.

I meditated after a long time and it lasted 1,5 hours. I started shaking after a while, then twitching my eyes, REM and after some time i started moving.. It was n a rythm. sometimes sideways, sometimes down towards the floor and so on. And when i wanted to stop my meditation i came back to my first position, then shaking, eyemovement, twitching and back to normal. Did something like this happen to anyone? Is it a good or a bad sign?
Thanks :)
In short this can be due to:


past fabrications surfacing rapidly and creating uncommon experiences
perhaps less likely but a possibility is Piti which sometimes create vibrating and / or pulsating experiences


Also see: eye movement during meditation, I get rapid eye movement as soon as meditation starts

These experiences are neither good nor bad. Also do not get attached or averse to them. In additions concentrate on the task at hand than giving importance and distracting your self when there experiences do arise in your meditation session.