Is it normal to get sudden jolts of fear for no reason?
Last night as I was trying to fall asleep I got this sudden jolt of sheer terror, I jumped up into a sitting position and was breathing really heavily. It felt like I was dying. I didn't have any idea what to do so I layed back down and tried to forget about it when suddenly it happened again. Same thing as last time, sudden panic with no foreseeable reason. In all it happened around 4 or 5 times until I finally managed to fall asleep.
Has anyone else ever experienced this or know why something like this would happen?