My 5 1/2 month old dd has been sleeping poorly. She was sleeping in bed with me until she learned how to roll on to her belly. Once she gets on her belly she can't get back onto her back and she puts her face down and cries. I have a pillow top mattress so I didn't think it was safe anymore. Anyway, now she is such a restless sleeper. She tosses and turn and throws herself. The only time she sleeps calmly is on a soft surface. I think I got her to used to my soft mattress. What do I do now?