I have 2 kids.
Now, young kids, act like this when:
1) they are over-tired
2) are hungry
3) are over stimulated
4) there is too much going on at one time
5) they are overwhelmed
6) they are rushed
7) and yes, when there are TOO many people, saying things to her or contradicting or allowing things. A young child like this... cannot... self-direct and handle, all of this commotion. They are young.
When things like that are going on, a child has, nil... patience and capacity for gauging themselves. And no coping skills.
ALSO remember... that children this age and even Kindergarteners... DO NOT YET have, "deductive reasoning" nor, fully developed deductive-reasoning.
They are 'now' reactors.
Not past tense.
Your child is typical.
Keep in mind that 3 years old is HARDER than 2 years old.
2 years old phases, are nothing.
4 years old is also a hard age. For the child.
A good book series is: "Your 3 Year Old", "Your 4 year Old", "Your 5 Year Old", etc. From Amazon.
It is easy to read and simply explains, what a child is like, at their age juncture.
Although written years ago, it is still very pertinent and good.
Kids this age, also, DO NOT HAVE, fully developed 'emotions.' Nor the absolute comprehension of their emotions, nor can they even accurately analyze themselves or their emotions and cannot... express it, succinctly. It is developmental stages.
So... that makes them frustrated. And the parental expectations, needs to be in tandem with their age and development.
You teach your child:
the names of feelings/emotions
how to say it
that she can say it to you
That even if H. or grumpy, she CAN say it and be heard.
I taught my kids these things from 2 years old. By 3 years old, my Son could tell me is he was "irritated", or "grumpy" or "frustrated" and KNEW the differences in it. He KNEW himself. And could say it and tell me and I'd help him... or teach him coping-skills for it.
He could also tell me, if he just needed to vent or unwind by himself. Or not.
But regardless if grumpy or H.... I made sure, that he KNEW we were a "Team" and that we helped each other, and that he could tell me anything he needed, to.
These are 'skills' that is taught.
It is not inherent, in a child.
At this young age, they need to be taught, about feelings and ways to cope.
Some Adults, don't even know that.
It is taught. Over time.