How do you shut down emotionally?

I REALLY don't know how to word this any better, but how do you like... shut down emotionally? I'm tired of getting upset over the smallest things that I have NO RIGHT to be upset about, yet my heart/brain can't help but hurt every single time and I don't like it. I feel childish and immature, I shouldn't be childish. I'm turning 15 soon, and I don't like how I react to things. I also don't like how people just... easily talk to others. I feel like dying every time I have to publicly speak to others because I feel like deep down they're going to judge me and they're going to dislike me. I feel like everyone secretly hates me and I just can't help but HURT from it. Is this a me issue??? I feel like if I talk to them about this they'll hate me more and I'll shut in even more and just not talk about anything. We're getting to the part where I highkey kinda get suicidal in detail and personal so pls beware of that <:(

>!I can't keep doing this. My emotions are a burden and if they're a burden they should be removed. It's either I emotionally dissolve or I genuinely just kill myself. It's so selfish, the way I think---how I claim to care for others, yet once I think about myself and how I feel I become selfish as to want to take my life away. I can't talk to my mother because she'll either end up crying, tell me to calm down, or to turn to god. I'm so tired. Why can't I talk to anyone? Why can't anyone talk to me? Am I that much of a burden to this world? I want to run away and never come back---to lie down with my chest open and my own pulsating core in my hand. It's been years, and no one has seen my true self. No one can see this beating, aching heart, and it's HURTING me.!<

... But maybe I'm just being severely dramatic and emotional, pls lmk...