some kids are worse than others. ive had little ones walk in and not even say bye to mom their first day and then Ive had what you had.
Give it a month
I selected a special spot for meltdowns after the second week. it is not time out. just a spot to go and cry when she has to that is out of the way of the other children. then make a huge show of having an AMAZING time with the rest of the kids, because she will be watching. Every few minutes ask her if she is ready to join. she could be there almost all day at times but she will begin to learn to calm herself and start to take interest in what you and the kids are doing
This to shall pass