Is she waking you to go out and pee? Is she hungry? If she acts really hungry, test her for tapeworms or even roundworms. Cats can get really hungry if they have worms. Also, be sure that she can get to her catbox.
yes I was going to say she is trying to tell you something , food ,water , company something wrong and I would say if she is inside loneliness may be a factor ...
Make sure you check her water levels before you go to bed and make sure there is at least a tidbit of dry food for kitty to nosh on during the night. Get a white noise CD and have your CD player set on repeat. Or, get a white noise machine. My kitty has gotten so used to the white noise that she runs into the bedroom when I turn it on, because she sometimes actually wants to sleep with me. Not always, but she is a very loving and affectionate kitty. Ignore the kitty so long as her basic needs are met so you can sleep through the night. Cats are very clever and they know how to manipulate their humans. Kitty is probably doing this for attention and will keep doing this unless you find a way to ignore kitty so you can sleep through the night. And, kitty may actually feel lonely and knows you will respond. Some cats enjoy having another cat around, but be careful if you choose to go that route because cats can be very territorial, too. Others with multiple cat households would be better at advising this.