Daughter says, "you don’t love me anymore"

My only daughter, who is 4 now, is full of tantrums and emotional outbursts. Every time she does something unacceptable and I raise my voice or point my finger, she senses my discomfort and has automated it to the statement “you don’t love me anymore” and she cries bitterly.

She pushed me while I was doing a headstand even when I have told her many times not to do that.

I am struggling here because she thinks it’s all play, but for me, it’s a strict NO. And the disciplinarian in me wants to lay out boundaries that seem very harsh for my level of discomfort.

Also, hearing her say repeatedly that I don’t love her anymore makes me feel horrible. I fear I’m already messing her up for her future.

How do I approach this situation and create boundaries which I use strategically and not for every naughty mistake? What is a hell NO?