M.M.
Oh boy, I could've written this post myself. We just transitioned our 2yr old to a toddler bed (crib conversion) because he was climbing out. The last 3 weeks have been hell. He used to sleep so great!
Now bedtime is a fight, and for the last week, he's been all over the map - waking up some nights several times, some nights not at all. The worse was Monday night. He was up from 12:30-4 just screaming. He wanted us in the room with him, which has never, ever been a problem before.
I'm chalking it up to a) bad dreams b) 2yr molars (maybe) c) a growth spurt and d) he knows that a new baby is coming very soon (I'm ready to deliver any day now).
We've reversed the handle on his bedroom to lock him in there. We don't let him sit and scream, but we do let him jiggle it for a bit before we go in. He needs to understand that night time is for sleep.
I literally just said to DH this morning, that I'm giving it another week, and if it's still a problem, we'll do CIO it again. I went in 2x to sit with him and tuck him back in last night (12:30 and 4), and I CANNOT deal with this on top of a newborn. Like you said, it's about his well being too, not only us. He's not sleeping well and is tired and crabby during the day (I forgot to mention that he's also stopped napping during all of this). So CIO will be the decision if this does not calm down on it's own in another week. It's always worked very well for us.
PS: a crib tent just seemed like prolonging the problem to me. It's clear that DS is ready to get out.