Sometimes I get this feeling when I am having a nap or at night time maybe 30 minutes to an hour from falling sleep. I just wake up suddenly my heart is beating very fast and the fear takes over, I sit on the bed for while waiting to see what happen but the fear is extreme like impending doom and takes me and after a while I calm down.. If it happens while I am having a nap I feel panicky for the rest of the day, and when it happens at night time I cannot go back to sleep because I am fearing that something is going to happen to me.
Sometimes I link it with stress, when it happens is usually after an stressful day.
Anyone can relate to this?