What to eat.....

Someone has refused to eat all day at nursery and chosen, instead, to cry!
I picked her up early and within a minute she was chattering away and her usual self.
When we got home I said 'tea time' to which she walked to her high chair, stretched out her hands and waited to be lifted in.
She ate two whole rounds of toast (the dark lord that told Audrey to just eat toast, has now visited us too), we also managed to squeeze in some twiglets, breadsticks and a petit filous.

So my question tonight dear blip friends, is.....
What do I do about this?
I can't bear the thought of her being unhappy at nursery, but to nursery she will go. How is it she refuses to eat all day there, but then comes home eats / drinks and smiles?