Your cat might be stressed out. Do you have kids? Are you moving? Have a new baby? Moved a piece of furniture?
Almost any little change can stress a cat out. Otherwise, I really don't know. Sorry.
I don't think you need to worry about this. Most cats don't like to cuddle anyway, including my cat. Cats usually choose when they want to snuggle and play, so it is best not to try to play and give your cat a lot of attention when they seem to be relaxing or trying to sleep.