I do kknow this post makes me sound like a crazy person - I'm not, I promise!
I have a lovely lovely tortoiseshell cat, I've had her for 6 years since she was 4 months old (RSPCA rescue cat). She is spoilt rotten with affection and love, but not with food, IYSWIM, goes out, kills things, brings me them, squeaks, cuddles, climbs trees, plays fetch and sleeps on my bed and chirrips away to me. She's got a cat buddy who she loves / hates, a regular supply of birds, entertainment, playtime and hunt and kill games, real or pretend 
However.
In the last week she has started to wake up at stupid times (ok, she is a bit like a baby and will wake up at various hours but this is different) and will go and pull and scratch at the carpets like she's digging. Desperately. She's not gone in her litter tray, or done her business anywhere, she's just frantic on the carpet.
I've taken her to the vet and nothing is wrong, she's fine.
What can I do? I love her to bits, she's clearly distressed and I don't want her to be, and my carpets are getting a mauling 
Any ideas? The vet hasn't got any...
I sound insane. Maybe I should have namechanged.