We've had a Tortie for some years now, and for as long as we've had her, she's
exhibited what we and only guess are nightmares.  She'll be sleeping soundly,
then wake up screeching until we find her and pet her.  It happens about once
a week on Monday morning... no, just kidding about that part - but once a week
is about right for her.  The only thing we could figure was that maybe
something happened to her before we got her and she's dreaming about that?
She's ok physically