Losing my balance

[Ampresus]

Hello everyone. This might be off-topic, but I think it belongs here. It doesn't have anything to do with meditation etc. At least, that is what I think.

When I was young and would try to sleep, I would lose my balance. I would feel like falling even though I was clearly just laying on my bed. Literally it would feel like I was on the edge of a skyscraper and about to fall. I always would 'safe' myself by making sure I am still laying on my bed. These weren't dreams, since they could happen like 2 secs after laying on my bed. 

Anyone who has experience with this and/or can me explain what it means? I basically lost my balance several times while trying to sleep. 

[nightrider1435]

I've had this happen to me before but it has been awhile. But yeah, it just felt like I was free falling and I would wake up with my arms and legs spazzing out, only to realize I'm in my bed... Not falling haha. I'd be interested to see if someone had some sort of explanation for it.