It must be very worrying for you, I think if it were my daughter I would try to encourage her to talk about her feelings and open up in a more appropriate way. It might sound like a silly idea but try giving her a small 'stress ball' or something that she can squeeze or fiddle with when she feels these emotions creeping up on her. It might be just what she needs to remind her to stay calm.
I am assuming she does not have any other worries at school, ie bullying or lack of friendship groups, is she very shy? I hope you find a way, good luck
check out this book by john gottman- i have posted on it before-it outlines really helpful ways to deal with your childs emotions and help them to identify how they are feeling and what they can do to feel better-its called 'the heart of parenting-raising an emotionally intelligent child'it also has a lot of ideas as to how parents can learn to 'coach' their children through different emotions so that the child learns about their emotions and how to identify what they are feeling and why. i would really encourage you to check it out. good luck!
