Partner and I have major blues, can’t seem to get puppy to engage with her crate

My partner and have a 12 week old puppy, when she was with the breeder and we visited her we could see she was happy to get into her crate and the breeder reported she was sleeping in her crate happily every night while the breeder slept in a different room. But now that we are home with her she refuses to stay in her crate, she will go in and out a bit but won’t try to sleep, only sleeping on one of us when we sit down. We put her in her crate at night but everytime we visit to get her a potty break she is trembling, even if she doesn’t cry at night. We aren’t sure what we are doing wrong but we both feel like we are failing our little puppy.