Sleep sack?

Shelby • 👼🏻👼🏻👶🏻👼🏻👼🏻👼🏻👶🏻

My 20 week old has been sleeping in a magic Merlin knock off and loves it. Sleeps 11 hours every night and it’s wonderful. But this morning I looked on the monitor and he was on his belly. Since that’s not safe, we are attempting a sleep sack tonight and it’s horrible. He’s woken up 4 times already and it’s only 10:30 pm. 😭. Has anyone transitioned to a sleep sack yet? How long did it take your little one to get used to it?