Our DD is generally a happy, chatty 5 year old who has settled well at school. She has always been strong willed and her teacher has just informed us that she is concerned about how she sometimes reacts when things don't go her way. She just goes completely still, won't talk and won't participate. Once she's come out of this 'mood' the teachers find it hard to get her to describe what she was feeling and they are worried about this propensity to internalise her feelings.
We have seen it two or three times out of school - all of the occasions have involved interaction with her peers. She can also have tantrums which we usually let run their course. I ask her afterwards what made her so upset and she shrugs her shoulders or says something general like she felt sad and won't elaborate.
Any advice on how we can get our DD to talk about how she's feeling? Should we be concerned or will she grow out of it as her vocabulary to express herself increases?