My puppy is almost 5 months old & has been sleeping through the night in her crate since I got her at 8 weeks old. She typically goes to bed around 11pm & would wake anywhere from 6 to 7am. Well, the past week she has been waking up at 3am crying nonstop. I take her outside & she eliminates herself. I can't understand why she all of a sudden can not sleep through the night. Can anyone help me?