So would it be out of keeping to use "dreamed" for a nightmare?

On the (rather rare) occasions when I was recalling them I always said "I had a nightmare." Using "nightmare" implied, rather strongly I thought, that I was dreaming at the time rather than nocturnally dealing with brumbies. In fact, the only animal that appeared (in recurrent dreams I recall from my adolescence) was a boomer, but that's another story.

Cheers, Rowan