How do I deal with my very "Stubborn" Mom

My Mom is the most stubborn person I've ever met. She always thinks I have a tone about something I say. She says I always have an attitude. One time I was doing the dishes and I got soapy water splashed into my eye. So I turned around making a frowny face and my brother was there. He went upstairs and told my mom that I made a face at him. She said she believed him. This is what got me really upset. He is 6 years old. why are you believing everything a SIX year old says? Now I'm upset and start crying. Now My mom is yelling at me for crying! She said that I was disrespectful. She didn't even talk to me for the whole day. to be fair I didn't want her to.
SHe is so stubborn that when I asked her a question she didn't hear it. I said it again and she said was that a tone? EVEN MY DAD SAID IT WASN'T AND I DIDN'T MEAN IT LIKE THAT.
Help me!!!

(P.S. She's sending me to therapy)

If I were you I’d make sure to call a relevant child mental welfare hotline and tell them about your situation. They’re acquainted with these things. The situation you just described is not healthy and is serious.
If you can’t because you’re afraid that your mom will find out, tell the school. Tell them your concerns and what should be done without letting them alert the mom first. Oftentimes the school contacts a relevant hotline to help if they do not have the necessary counsellors.
That being said, I don’t know the full story. Things may be recalled differently to how it actually happened depending on how you felt at that specific moment, and maybe your mom is going through stuff that also might need to be acknowledged.
Do what you know is right for your mental health.

Hope all turns out well soon.

(P.S. She's sending me to therapy)