Extreme 3 old tantrums

[mwilliams58]

My daughter was 3 in January and to be honest I don't even really know where to begin! She has always been quite wilful and spirited and pushed boundaries but just recently I'm really struggling to understand her and her behaviour.
I had a baby in February, a little boy, and I'm sure some of what has been happening is to do with that but not all.
She has taken to having the most extreme tantrums over everything. You cannot disagree or ask her to do anything because she screams and shouts and kicks off completely. It is horrendous and she can keep going and going. She'll shout and shout and she doesn't care who sees her.
She also overreacts to everything. If she falls over and cuts her knee it's not just a case of crying because she's hurt herself she'll scream and cry and almost have a massive tantrum over it. She constantly cries when interacting with other children because she can't understand if they don't want to do what she wants. She cannot share at all and gets quite nasty about it sometimes.
Over the last few weeks she's become strangely shy and will avoid speaking to anyone even people we've always known. She'll even just point rather than use words sometimes. If you ask her to say hello she'll throw herself down in a strop.
She is exhausted after 2.5 days at pre-school but she never seems to let herself relax or recharge. She behaves as if she's constantly tired and looks incredibly tired too.
I've spoken to the pre-school and they haven't witnessed any of this behaviour. They say she's funny and gets involved and is a character.
She has this hyper mood at the moment too which is almost manic. She wants to constantly run around and shouts so loudly if you say no. She laughs almost manically and it's very hard to calm her down. It's really really silly.
She's a very very clever girl and is intellectually advanced. Sometimes I think this weighs heavy because physically she can't match her mind. Her speech is amazing and she never stops talking at all.
I am at a complete loss which is why I'm lying in bed writing this and trying to see if anyone can offer any help at all. Thank you xxx

[ppeatfruit]

Well I reckon she may be allergic to something, sugar ? Wheat? Does she get hyper after these?

I wouldn't ask her to say hello she's not a doll. Saying 'no' does generally upset children (and adults) have you tried playing games with her like making her toys speak, or getting her to dress them while you help her to dress There's a good book that might help you called "How to Speak so children Listen and listen so Children speak"