My DD is 4 months old & has just started rolling over onto her tummy as soon as she is put in her cot. I wouldn't mind as much if she turned her head to the side, but she buries it in the mattress! She sleeps loads better but she worries me to death... What can you do? I've tried propping her so she can't roll over but she cries until she gets comfy... ON HER FRONT!!