Emotional Regression - 4 year old

[WomanInTheMirrorStaresAtMe]

My four year old is showing some behaviours that I am concerned about and wondered if anyone had any ideas or if I should investigate further...

Basically whenever she is nervous, or upset or something new happens (visit new place) or in a crowded place... She will regress emotionally - she will talk like a baby, misbehave, hit out at people, basically act like a 2 year old. She is normally articulate and intelligent. She is very loud and daring, climbing and jumping and seems to have no fear.

Other behaviour that worries me is she makes up elaborate lies/stories, she seems to lack empathy at times - for example her sister was hurt but she was unmoved by seeing her cry and just wanted to get on with the game they were playing. This sort of thing is common with her.

She also struggles to recall things, her long term memory is fine but if you ask her what she did yesterday she won't be able to tell you and will likely make something up. She is sensitive to loud noises, I have had her hearing checked and it's fine.

Does all this sound like part of her growing up or could there be something else.

Her preschool say she is hitting all the right markers in developing except for emotional development where she struggles to see others viewpoint, have empathy and gets herself very upset over things when they don't go her way.

Anyone have any experience of any of this??

My dd was a lot like this at 4.
She did the baby voice a lot and we found it very annoying.
She had stopped hitting out at other children by the time she was 4 (she only started at 3.5 when her brother was born) though she’ll still hit out at me occasionally even now. She didn’t make stuff up, but her same age best friend made stuff up constantly at that age as did other 4 - 5 year olds I know, so I’m sure that’s a stage many kids do go through.
My dd is also impatient and tantrummy (still at 5.5) when things don’t go her way. When I ask her what she’s done at school today she can never remember, but that’s quite normal like most other kids in her class. The other day I asked a group of them “what did you guys have for lunch today?” and the group of 5-6 yos spent 10 mins discussing it until one finally remembered!
Her empathy is variable - she often ignores it when her siblings are sad. Or laughs like small psychopath! She can also be thoughtful and loving at times too, but I notice that her 2 year old brother is already instinctively much more nurturing than she is. She has plenty of other lovely qualities tho. She’s fiercely loyal, for example, and very brave. And very enthusiastic about almost everything. I’ve chalked it all up to personality.
Dd is socially happy now at school with plenty of friends. Her temper and frustration tolerance were slowly improving, though she could still be very dramatic when tired. She stopped doing the infuriating baby voice a few months back. In the last couple of weeks Shes made a huge social leap and her empathy and control of emotions have improved vastly, almost overnight.

So to me, it just sounds like one of those things - some kids learn to read easily, others need more time and help. I guess some learn to manage frustration and consider others more easily and some need more time and help too.
The things you’ve described are all phases my dd has gone through or other children I know at that age, so I don’t suppose there’s any need to worry, just work on finding ways to help her with the stuff she finds hard.
There’s a book I think might be relevant. But the name of it escapes me, though I’ll post back here if I remember.