don't know what to do

Olivia has always been the one that liked school, she was always ready to go even when they didn't have it. Alex always wanted to sleep in and stay home with me and meme. Well Santa came a few weeks ago and scared Olivia half to death. Ever since then she cries everytime we drop her off and her teacher says as long as she is on her lap she is fine, but when she puts her down she cries again. I have told her Christmas is over he isn't coming back, but that doesn't seem to help. I'm at the end of my rope I have no idea what to do. I pray everyday that she will understand that I wouldn't send her if I thought he was going to be there to scare her. Please pray that she feels safe and will not be scared anymore.