Natasha love, I think its probably related to whats coming up. I agree with LCM.... you might just have to ride it out & in the meantime try to keep her rested by offering earlier bedtime. Things were really up in the air when Jasmine was born for a few weeks (night wakings, short naps)... it only lasted a few weeks here so hopefully Catherine will go back to sleeping well soon for you.
Is DH going to be around for a few weeks when the bub is born?