Dd1 is 5. She went out with a schoolfriend today and since she got back her behaviour has been appalling, really erratic and quite upsetting. She isn't perfect - in fact I've started a thread in the past about the fact that I get sick of asking her to do things several times before she listens - but generally she is a good girl, bright and fairly calm. Today we've had four hours of hell and she's still awake. She has gone from downright disobedience and rudeness, writing me letters with rude words in, then tearing them up in tears and saying she didn't know why she did it, to hysterics which she told DH were because she had thought something so bad about me she couldn't ever say it but it wouldn't go out of her head, and sobbing that she was rubbish and didn't like herself and everyone hated her (we tell her never to use that word). All this was done whilst racing round the house and being very agitated physically. This lasted about two hours, then she became what I can only describe as "high" - bouncing everywhere, kissing dd2 until we had to stop her, shouting all over the house that she loved us and loved everyone and so on.
This is completely out of character. Her eyes are swollen from crying and some of the things she said - particularly about herself - really upset me.
The only thing I can think of that might explain it is that she went with the friend to a well-known chain of family friendly pubs and had ice cream from a machine with lots of garish coloured toppings. We've only ever let her have that once at another child's party a year ago and it made her sick.
I'm not jumping on the Jamie Oliver bandwagon - haven't really watched it although I'm aware of what he's saying - but can anyone else think of another reason why a normally happy and even-tempered child might suddenly turn like this?