Surreal feelings / Venting

I feel like I need to talk about all of this and get it out of my way. When I was 12 I shot my sister's boyfriend. She was 17 and he was 18. I didn't want to but I didn't know what else to do. He would've hurt her (or possibly me) if I didn't.

Both my parents were at work and I was home alone. I didn't go to school that day because I was sick. Some days my sister and her boyfriend would skip school together and that day happened to be one of them. She left for school earlier in the morning than I did so she didn't know I had stayed home. I was napping in my room when I heard them arguing in the living room. He was yelling at her about all kinds of things that I can't and don't want to remember. I recognized his voice and went to see what was going on. I saw him holding a kitchen knife and backing my sister into the corner. She was crying, he was screaming at her, and it all felt like a dream. Like it wasn't real. My mind was in denial of what I saw. He kept pointing the knife at her neck and waving it all over the place. I didn't know exactly why he was so mad but I knew I didn't want to see my sister stabbed in front of me. I went to my parents room and grabbed my dad's gun. It was the first and only thing I could think of.

I had never liked her boyfriend. I always thought he was an asshole. He gave her bruises all the time because he was "stressed" or "frustrated" with her. Once she saw me looking at her bruises and begged me not to tell our parents. Normally she wore makeup to cover them up. I didn't tell anyone because she was my big sister and I didn't want to get her in trouble. I didn't fully understand what was happening to her. I thought maybe the bruises were just an accident.

I was terrified of accidentally shooting my sister or even myself but I took it anyway. I didn't even know if it was loaded. I didn't really know what to do with it. I just wanted to scare her boyfriend away so he wouldn't hurt her. I came up behind him and told him to put the knife down. He turned around and looked shocked at first but then he started mocking me, saying things like "a little girl is going to shoot me?" and "you don't even know how to use that".

He came closer to me and tried to threaten me into putting the gun down. I kept backing away from him and telling him to leave me alone but he kept getting closer. I was about to hit a wall when I finally just panicked and shot him in the leg. I was aiming for his foot but then again I was 12 and not trained so... best I could do. He was on the floor bleeding, my sister was crying hysterically, and I was beyond traumatized. I was shaking and immediately ran to call my mom who then called 911.

Worst day ever. The boyfriend ended up fine but went to jail (with multiple charges). When I think back on it now (this was a few years ago), It all feels so bizarre. Like I was disassociating the whole time. The feeling is so weird. I guess that's my response to stress. Nowadays I can't handle people yelling. It brings me back to that day. I hate arguments too..... Ok bye. Had to vent for a little bit. Any advice for getting over this event and 'letting go' of it would be greatly appreciated.

(My sister is fine now, she's currently in college with a new boyfriend who won't try to kill her <3)