What to do after getting shouted at?

My mom yelled at me very often
It didn’t affect me much
But one day it affected me a lot
Not able to get over the anxiety
It keeps coming back in the form of heart rate rising

I suppose you need to nurture the terrorised, traumatized part of yourself that was yelled at so that your pain-body/trauma isn't triggered by the very suggestion of shouting, noise, anger, aggression.

You’re right. Is it okay if I tell you the context of what happened? Incredibly sorry for the following story which I have written in detail: My dad had gone out for three days. He was in another city, gone for work. My sister and mom were with me and would go to work during the day and come back in the evening. I would be at home, feeling bored. (I had dropped out) I was already feeling lonely that my dad wasn’t there, and then my mom and sister took my dog to my grandmothers house (1km away). I was almost in tears.

Here’s an excerpt of the texts with my sis:

Me: “hey sis. Can we bring the dog here?”

Sis: “I would like to keep him with me”

Me: “I feel distressed that he’s not there”

Sis: “I don’t know what to say”

Me: “For some time, till I sleep, can he come here?”

Sis: “Idk”

Me: “Okay”

Sis: “I'll think and let you know. I feel I need him with me at the moment”
I put a thumbs up.

Then my mom came from my grandmothers house. (Both of them had gone there and I was all alone)
I was in a foul mood and I wasn’t talking
She said it’s my own fault, I brought it upon myself. If I had not behaved rudely she wouldn’t have taken him away. She tried to punish me by taking my dog away at a time when I was already lonely. I didn’t have the patience to bear it.
I believe she blamed me saying I shouldn’t have done something a certain way, to which I got increasingly enraged and screamed and banged the table and laptop. She tried to hug me but I pushed her away brusquely, it bordered on a punch more than a push. Regretting what I done I sat there stunned for a few seconds.
I got scared that I did that. I never wanted to. I went to my dad’s room to sleep as soon as I could to avoid any further problems but she followed me. She shouted and I argued with her. I wish I had recorded it. She screamed and tried to get the demon out of me or something.
“OUT! OUT!! IN THE NAME OF JESUS, GET OUT OF HER!!”
But it didn’t work. I was rude as ever.
Finally she left and I swiftly locked the door. Then it happened. She knocked at the door. She said “open the door…” She began banging the door. It got louder.
She tried the handle and pulled it up and down making a squeaky yet rough metallic sound. She struggled at the handle, ‘shik-shik-shik-shik-shik-shik!’ she tried the handle. I curled into my bed sheet And waited. Then she began to thump the door louder and louder, saying “OPEN THE DOOR!” She cried desperately. She wanted her nightclothes but this was my dad’s room. All her clothes were in my grandmothers house and some in my sister’s room. I knew she was lying, trying to scare me to open the door. If I opened the door, she would have not spared me. She said “people are starting to crowd here,” (I thought the front door was open and people had gathered to see what’s happening.) but there was no one outside when I later checked. “I’ll call the security” she said
I didn’t budge
“I WANT MY CLOTHES!” she wailed. After what felt like 10 minutes of continuous pounding the door and crying she let out an almighty wail “MA! PA! SAVE ME! LORD JESUS HAVE MERCY ON ME!” And she cried and cried like a child and prayed outside my door loudly. I closed my eyes and slept after she quieted down.
The next day she came with my sis and gave her a hammer. Instructed her to hammer down my lock. And they broke it.
Here’s what I think. I agree I was scared and crying. I was lonely. Which means this feeling of pain in my throat or chest got compounded when this happened. It added to pre-existing pain. What was this pain? Why was it so intense? That I screamed and hit my laptop? Till date, I feel a dull pain in my throat. It’s obviously a part of me in pain or feeling anxious. Because when she cried for help, a part of me felt guilty, maybe pity on her, but a part of me refused to budge. A rough, rude and protective shield. It was willing to be seen as a villain in order to protect me. “It’s okay,” it said. “Let her bang the door. We ain’t opening it. Because you matter right now. There is some hope in staying put. In being quiet. In refusing to open the door to your room, or to your heart. She may not understand you, and she’ll talk over you. She’ll be self obsessed and who knows if she cares about us? She took our dog away. First the cat, now this? No way. And what about all the times she made you cry and scolded you for crying? All the random anger she took out on you? Stay put. Don’t move.”
Perhaps bit by bit it happened so. It wasn’t one terrible attack that made me lonely. It was day by day, year by year. It bolstered my fears of being locked out and ignored. Of being made a scapegoat. Of being blamed for their own burdens.
I’m not sure.
By the way, my opinion is, my therapist is trying to get me to remember my memories and feelings from long ago. It is particularly challenging for people who don’t journal. But I have a card up my sleeve. I have journaled for 9 years now, since I was 10 years old. I have a fair amount of insight into what happened in those days and how I felt too.
We’ll see what happens when I go to therapy for my next session.

I had a T who ''specialised'' in that.

I think nurturing the traumatized part of you would help.