This may be a long one... But I need to vent one way or another.

I'm a 14-year-old preteen. I feel tired of this world, sometimes I want to disappear for a long time and that the people I love don't care about me. I have not been able to ask for help because I feel that my problems are nothing compared to other people's problems. “You're a teenager, what problems can you have” is what I always say to myself when I feel bad. My parents went to “get” a better job when I was 3 years old and never came home, we only spoke by message but I never considered him a father since he didn't win that title. I lived with my mother since childhood, she dated men (I never got mad since she has the right to date who she wants) during my childhood I met several of her boyfriends until one day when I was 8-9 she introduced me to her partner and she was good and kind to us, that didn't last long since at 2 years of relationship everything took a 180° turn degrees. He was an aggressive alcoholic who hurt my mom and yelled at her, whenever he drank I was around my mom to take care of her. Once he tried to strangle her thanks to a small fight that my mom and her husband's grandmother had, since then every time they have a fight I feel close to listen and if at any point the fight turns aggressive being able to be there to help my mom.
Although my mom took care of me, fed me, gave me a roof to sleep in, it's not always as good as it looks.

She “educated” me in an aggressive and hurtful way, both physically and psychologically, I never felt comfortable telling her my problems because she would surely tell me “nothing happens” “I have more serious problems than you” “your duties are just to study and clean your room”. Both she and my maternal family (especially my grandmother, my mother's second sister and my aunt's husband) treated me in a very dismissive and hurtful way, they lived it by comparing me to my cousin, criticizing my body, scolding me senselessly, making me feel less, etc. After 3 years my mom married that boyfriend who now “no longer it was bad”, months later my younger brother was born (I was about 12 years old) I sincerely envy him because they give him more attention and treat him better than me in many ways.

It is okay that they treat my little brother well, he is not to blame for the mistakes they made in the past... but, what about me? Why don't they treat me better?
Why are they yelling at me so much?
Why don't they love me the way they love him?
Are they forgetting about me?
Hassle in your new family?
Even... Do you consider me your family? I am so envious that if he has a father figure present, a mother who shows him love, some new grandparents who treat him well... WHY DON'T I? WHY DID I HAVE TO GROW UP AT A VERY YOUNG AGE? WHY DON'T I HAVE HIS LIFE? WHY DO I FEEL SO BAD? Mommy, why don't you love me as much as you love him?...... 

Even though I'm so jealous and hated my younger brother... I would give my life for him, I would be able to kill someone so that he could be happy, I would take my life so that he could be the only child in this “family” and the three of us could be happy together.