This particular nightmare isn't the worst situation I've been put in, but it gave me the worst feelings.
I used to dream in recurrence of a massive coliseum. I would always start in the very center. The wind would blow. The sky would darken. The Velociraptors would charge in and tear me to shreds. You know, normal nightmare stuff.
One time, there was a Deinonychus, too, but I don't know if that's significant.
If I have to go deeper, I'd pull a Freud and say the sky represents the future. As a little kid, I had no idea what it hold, and I was quite the pessimist, so it makes a tad of sense that this dream stems from my fear of the future, or perhaps the outside world.
The dinosaurs probably represented other people, beating me at life or something to that effect.