please help me get some sleep

Hey! My 6 week baby girl will only sleep soundly on her tummy. I let her during the day because that's the only way she naps but I stay awake so I can check on her. At night she'll only sleep on my chest. I go back to work soon and I really need help getting her to sleep in her pack n play next to our bed. 
(EBF, won't take paci or bottle. Loves being swaddled but she'll still wake up when on her back)