Leaking out of diaper

How can I keep my Lo from leaking out of his diaper during the night ? He is 5 months old and just started sleeping through the night. Now that he is sleeping through the night and rolling he is laying on his stomach for most of the night and when he wakes up for the morning his whole front is soaked with pee. It’s on his clothes, his zipadee zip sack and even his sheets. I tried double diapering him and it still didn’t work . He must be leaking through the top of it. He’s only in size 2 diapers so I have not seen overnight diapers in his size . What can I do ? I don’t want to wash sheets and sleep sack every day.