I feel like I'm always in 'that state', constantly sleep deprived. For example, two nights ago I was up until 10am working on projects (for work... clearly), slept for 3 hours, only to stay awake again until 5-6am, waking at 10am. This is torturous.
I DO sometimes see little things out of the corner of my eye, get that odd paranoia, hear whisperings or music in the background (when there isn't really music). I can freak myself out pretty easily (esp with all the Criminal Minds I watch).