For the past couple of months DD has been sleeping really well in her crib for about 10-12hours. All of a sudden she will not stay in the crib at all. As soon as I put her down, she screams and cries. I tried laying her down and staying with her but she keeps sitting up and crying. I have tried playing music, reading books and singing to her. The only solution we have right now is that we are letting her sleep in our bed. How can I get her back in the crib? Is it normal for this to happen all of a sudden?