Baby is refusing to sleep unless held the last 2 nights. Why??

Baby will be 8 weeks Monday. He has slept in his crib in his room since 2 weeks old. He’s always had the same schedule of bath, feed, sleep. We feed around 7:45-8. He’s been sleeping 3-4 hour stretches for weeks now, and Tuesday and Wednesday night he even went 4.5 hour stretches. In the last 2 weeks, he has started fighting sleep for naps especially where I’m having to hold him to put him to sleep. At night I hold him until he falls asleep or close to it. Last night and tonight, he is asleep when I put him in his crib and within 20 minutes if not immediately he is crying from dropping his paci. We’ve put it back 3 times each night until it no longer works and the only solution is to hold him. Last night after 2am I was finally able to put him down and he slept in his crib but was up again at 4:45. He slept on me until I woke him at 6:30 to eat. I put him on our bed beside me on his tummy after that and he slept until 10am when I woke him to eat. What could be the reason for this sudden change??