Stomach sleeper 😭

My 3 week old will only sleep longer than 15 minutes if she’s laying on my chest, daddy’s chest, or napping on her stomach. She won’t sleep on her back at night at all, she’s up every 15 minutes screaming about it. She’s fed, clean diaper, burped, etc so in know it’s got to be being on her back. I hate it! I want her to be safe but we also can’t be safe if I don’t get any sleep at all. She’s breastfed and comfort nurses after screaming, we’ve tried letting daddy comfort her with rocking etc, doesn’t work. Help! How do I get her to sleep on her back?!