He'd Rather Sleep on the Floor

In early November, we realized DS (26 months) was climbing over the rail of his crib, playing, and getting back into bed. We promptly converted his crib to the toddler setting, but he REFUSED to sleep in it. He'd just started potty training on Thursday, his dog died suddenly on Friday, and Saturday we converted the bed. Just too much change at once, so we gave him the crib rail and just prayed he didn't hurt himself.

 Santa brought him 2 toddler bed sets. We talked up how Santa must think he's a big boy who's ready for a big boy bed since he brought big boy covers. He agreed to the conversion again and slept well in his bed for a week and a half. Now, he doesn't want to fall asleep in it. He'd much rather sleep on the floor or dog bed. I've found him in his floor, sleeping in the hall, and next to my bed. Sometimes, he just climbs in bed with us. It's the same mattress. We flipped it to the firm side when he was 8 or 9 months old. And, it's his crib with a toddler conversion rail.

We've tried laying in his room with him until he falls asleep and that just results in him playing or talking, then getting up in the middle of the night. I've laid the mattress on the floor in his room and it becomes a gymnastics mat. I've put it in our room and he sleeps on, but rolls into the wall and bumps his head, which causes him to wake up crying. If I pull it away from the wall, he back on the floor.. Anybody have any suggestions on how to get him to sleep in the bed?