Four year old crisis!

[LondonerWith2]

I need advice
For the past few weeks my 4 year old behaviour has been worse than its ever been x100
She's always been hyper and busy (completely NON stop from about 545 each day)
But the past few days she's been screaming at me when not getting her own way, punched her sister (1 year old) because she wanted her tablet
Told me she's gonna get her dad to beat me up , she hates me wants a new mum etc
When she's good she's really good, but when she's bad she's really bad, this has been constant for a while now and just don't know what to do!!!

That does sound hard to deal with.

If her behaviour has ramped up in the last few days, has something changed recently? Could she be ill?

Not that I'm aware of
She's been complaining about issues at nursery but when I speak to them they're unaware? She's still playing with same friends doing same stuff 🤷🏼‍♀️