Please help me sleep :(

A few weeks ago the power went out for a second in our home over night and my sons (3 y.o) nightlight/sound maker turned off obviously. He came into my room crying that it had turned off so I went in, turned it back on, and tucked him back in. He went right back to sleep.

The next night, and every night since, he will not go to bed. We’ve been going on 2 hours tonight of trying to get him to stay in his room. We have done absolutely everything I can think of from reading, walking around the room to assure him there is nothing to be scared of, the in and out consistently laying him back down when he gets up as soon as we shut the door, etc. If we let him fall asleep with us on the couch, or in our bed, we cannot transfer him to his bed or he wakes and the cycle starts again. If we lay with him until he falls asleep he will eventually wake up and it starts again.

I don’t know what to do. We have NEVER had a problem with him going to bed or staying asleep before.