Tummy Time while sleeping?

Last night before I went to sleep I, as normal routine, checked on Sadie a few times. On my last check of the night, since the last time I checked (10 min?) she had rolled her little self over and was sleeping on her belly. Guess that means it is official; Sadie is on the move. Problem is she did at 3 in the morning and woke up screaming because she couldn't get back over. Looks like we need to work on getting her to roll back again. Our sleep depends on it!