Can anyone help me out?

For starters, I have some great anger issues. It's not good, I know, and I'm stressed out of how this feeling actually controls everything from my personalities, my social circles, and the choices I've made.

Four years ago, I was jealous of this new girl in school because my best friend started to hang out with her all the time and I stayed in their background and already imagining killing all of them. That killing part didn't happen, instead, I "showed" my anger and became arrogant. Made the best friend cried and questioning why I "acted up". We later became normal again and nothing bad happened.

Two years later, I attended uni where I've found new friends with other people from different places and backgrounds and finally had a boyfriend. So soon after we broke up after we ended our course, I didn't want to draw attention and answering people's questions on why we broke up, so I unfollowed/unfriended and block all of them from social medias. Few of them actually sent me emails and messages on why did I do all that, but my arrogance was over the top, therefore didn't reply.

So earlier this year, something incredibly stupid happened that led that best friend from school and I not talking ever again. She said she was sorry multiple of times, but there I was: deleting the messages before I was able to read them.

About a month ago, some friends of mine who are older went for a getaway. I don't know what got into me and made me so angry because we were already receiving assignments to sent in by the seventh week and we haven't met the other members of the groupwork for a meeting. It wasn't an easy job being the youngest among the circle and all, and I literally thrown tantrums at them. So after their getaway, I thrown random shade at them and I don't know at first if they noticed. Afterwards, I came back to class and returned them the gifts they've got me (because I didn't want gifts, I wanted to see their progress with the work). One of them nearly cried in class (supposed we were "best friends") and I could see with that she was holding tears for two hours. I couldn't care less. Once the class ended, she came to me and her voice cracked, asking me if we could talk. I unleashed all that I've bottled up and tried telling her the best way I could.

The following day, we didn't talk. There was a chair next to me that was unoccupied and another friend invited her to sit next to me and we still didn't talk. She tried to made small talks but I was just couldn't be bothered to answer enthusiastically and in full sentences. The following week, I bumped into her and I didn't say sorry. She was so pissed, maybe? But again, I couldn't give a damn. So this lasted until today, the sixth week and next week is our presentation together.

I'm not a person who is able to confront anyone because I'm afraid someone would get slapped or worse still, ass-kicked real good. I'm not proud of this ego and arrogance I have and I don't wish to embed it in my personality. I already have no friends now, and I try my best to keep a straight face and look as happy as I could but inside, I'm just torn. I have lots of attitude problems and I don't want to live like this, unfortunately I'm still very passive-agressive.

Would be nice to hear your thoughts and help me to change.

Thanks and lots of love,

Yeol.