She had a recurring 'nightmare' [=she had the same bad dream many times] about losing her job.
Losing a child is every parent's 'worst nightmare'. [=the thing every parent fears most]
Mommy, I had a really scary 'nightmare'.
(..) - Don't make me laugh. - All right. Oh, you'll protect me? Yeah. I have a black belt, you know? Nightmares-- It's fine. Shh. Oh, fuck. Hey, what are you doing, little guy? Hey. (..)2008 Two Lovers
(..) some water. Thank you, Leonard. Feelin' better? Good. I had these crazy nightmares while I was out. Yeah? Don't worry. I am here to protect you. Ow. (..)2008 Two Lovers