Thanks ladies for the replies. Sorry to hear that Belle, its hard b/c kids who are outgoing don't understand why the shy ones hold back, and then the shy children think they aren't liked. My daughter has said plenty of times she doesn't think people like her, but then the next day she's had a note from someone or had a lovely time playing with a few girls and everything is OK again. I think she just worries about things a lot, I remember being like that.
After I left her teacher asked her what was wrong and who she wanted to play with, she said she didn't know, and then she said that he left. I don't know if that is accurate, but another girl came up to her and invited her to play. the school has never been very good about dealing with playtime issues, I will see how the rest of the week goes and if it continues will have a word with her teacher.