Won't take pacifier

Merium • Married since June 2014, momma to 2 littles 💗💙.
My LO is 3 weeks old and needs to suck to be soothed to sleep but she won't take a pacifier and I can't keep my nipple in her mouth 24/7. How do I get her to take the paci? I've tried 3 different kinds. She's taken 2 for a few min but then refuses it when I try again. Help!