Poor little guy!

We bought Nicholas a toddler bed on Thursday because Renae is needing to use the crib now.  She had been in the pack and play, but woke up screaming the other day because she had somehow slipped between the bottom and the mattress.  Scary!  She was still able to breathe where she was, but it was too close for comfort.  There is also a large hole in the mesh side of the pack and play such that Renae could easily put her head through it, and I don't want her to somehow get entangled.  So, she needs to use the crib now.  Unfortunately, Nicholas is so attached to that crib for some reason.  It's his comfort blanket.  We tried putting him in a makeshift toddler bed before, but that only lasted a week.  We thought that with it being six months later he'd be okay with it.  Ever since Thursday night when put him in the bed, it has been a struggle.  He'll scream, wail, whimper, and sob while pounding on the door to let him out.  This is unusual because Nicholas is actually a really great sleeper when it comes to falling asleep here at home.  Today at nap time he was so tired, but just wouldn't calm down to take a nap.  I needed him to take a nap, so I broke down and let him use the crib.  As soon as I laid him down in the crib, he stopped crying, and through his sniffles said, "thank you."  Then he flipped over onto his belly and slept for three hours without a peep!  I know that we have to just be consistent and he'll get used to it, but I don't want to traumatize this poor little guy.  Hopefully tonight will be easier on him.