I have a bunny that is about 6 months old. She is litter trained and lives in my room, but whenever I change her litter box she digs in it. She only digs when I'm in the room with her. Whenever I go to sleep she starts diging which makes alot of noise making it hard for me to sleep. Then in the morning I have big mess to clean up. The next day when the litter box hasn't been change she won't make a mess. Why does she do this and how do I get her to stop?