Hello Annette,
I read your message on your 5 year old daughter. My first question is, is she your first daughter or do you have other children older or younger than her? The first thing I would do is go to the school and see what is going on there, because there is definitely something bothering her at school for her to carry on like that, she has probably seen or heard something which she, as the child she is, is not aware of and that is making her react. Another question I would ask is whether she behaves like that at home or is it only at school? If it is only at school, there is definitely something bothering her there, either a school friend or a teacher who isn't up to par and whom she feels is not treating her right. Whatever it is, a child doesn't react like that out of the blue, there is something that is making her angry and insecure on the inside.