Sleep changes at 2? HELP ME

my son has been putting himself to sleep since 11 months old. He is now 2. We read books, turn out the light and snuggle in his rocking chair for 5-10 min snd then we lay him down. He says goodnight and falls asleep after 10-20 min. The last 3 nights, he has screamed the second we put him down yelling to come back and to sit in the chair. It’s happening to me and my husband. He won’t lay down and we are having to rock him to sleep. What is going on?!