Son Won’t Sleep in His Crib

Ma

Since we brought my son home he started sleeping in our bed with us. This was the only way for us to get any sleep. Around week 9 or 10 we tried transitioning him into a crib in our room which actually took. I’d feed him in our bed, he’d fall asleep, I’d wait 20 minutes then transfer him to his crib. No problem. He’d wake once or twice to nurse but would go right back to his crib. This past week (12-13 weeks old now) he all the sudden refuses to sleep in his crib. No matter how long he’s been asleep he wakes up almost immediately. The only thing I can think of that’s changed is that I went back to work but that doesn’t make sense for the first night he did this since I hadn’t went to work yet. Does anybody know why he all the sudden refuses to sleep in his crib after weeks of no issue with it? I can’t keep letting him sleep in our bed because I worry about him all night and end up getting very little sleep.

Any advice? No he doesn’t like being swaddled, we do put him in a sleep sack though. He also doesn’t like pacifiers.