Somewhere in kindergarten and all the other life changes comes more information and she might not actually be able to identify it. They hear something on the news that we don't know they did, such as Haunted House stories, or see ads, or hear other kids talking and they might get a little anxious. So that's one The next is that kids, even the ones with lots of friends can be anxious with all sorts of newness.
The next thing maybe the pink room is gorgeous but too bright? One of my sons rooms just never seemed to get dark enough.
Talk,talk,talk. It might go away on its own, but you will never look back and say I wish I would have talked to my child more. And if you know you are doing that, then you will be okay. All of you.
I remember my sons getting scared and we would let them sleep on the floor beside us until this passed. Believe me they do not want to sleep with you the rest of their lives. The important part is needing sleep. So sometimes you do have to adapt. MY heart goes out to you.