First of all, Im so happy i found this page! I was searching the Internet for an explanation of what happened to me. Im from Sweden and I found nothing about this in Swedish...
Two days ago I woke up between 4 and 5 and It felt like the whole bed was shaking hard! I sat up and looked around. But everything was still. Thats when I understood it was ME that was shaking! My heart beat so fast and so hard and my whole body too! I laid down again and after a few seconds it was gone.
Last night it happened again, but this time it wasnt as hard as the first time.
I had never heard about this before so of course I wondered if it was dangerous.
Just wanted to share this! Nice to find some answers, now I feel more calm!
One of those intrusive thought days
Just broke up with my BF having a massive panic attack. 
Body Vibrations Night Terrors 
Do you ever feel like nobody actually cares?