Used to have similar feelings (was prone to night terrors and nightmares for years)... never figured out what caused them... but they stopped rather abruptly within the last year or so (about the time I met my bf)... so go figure...
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen