5month old sleeping & rolling to belly

My lg has began rolling to her belly all the time now when I lay her flat. She starts out sleeping on her side but then turns to her belly. The problem is she doesn't no to turn her head to the side when on her belly. She instead try's to kick and move. She does turn her head to the side when I hold her and she falls asleep though. So our 11 hour sleep nights have turned into her waking up several times because she rolls to her belly. & yes it freaks me out since she doesn't turn her head!  Any tips?! It's exhausting when she was sleeping the night for at least 2 months & now she is up.