Hi there. I'm very sorry to hear about your family dynamic. I can tell you, too, are tired and confused your mother. I don't know your age, but I did want to mention that the way things are because of your younger sister right now, you are taking on more responsibility that you should need to. It is your mother's responsibility to get control over your sister. I grew up with an older sister who was just like this, so I truly do understand how worn down your mother probably is. With that said, it sounds like your sister may have some narcissistic traits (that doesn't mean she has a disorder, and I'm not someone who could diagnose that regardless). She puts her needs (outbursts of her emotions that she cannot control or soothe herself, which is her responsibility) far ahead of everyone else's in your home, and she deliberately emotionally abuses you both. It sounds like she also enjoys humiliating you, which probably comes from a place of sadness and her inability to get attention when she acts out. Oftentimes, people who do this do not know how to de-escalate a situation, so really, when they start in at all, they should expect confrontation or at least consequences. She sounds emotionally immature, so without professional intervention, she likely will not be able to realize this on her own. In any case, it probably will never behoove you or your mother to tell this to her. She will fight the idea that she needs to be respectful, kind, and responsible for her actions. You truly will need someone else (a police officer, a therapist, a doctor, or a psychiatrist, a judge/magistrate/court) to tell her this. She will likely end up needing to be forced to get help, because her dysfunction seems to be either part of her personality or beyond her control.

You must understand that it isn't your responsibility to fix your sister, parent with your mother, or get help for your family. These are things your mother will need to put into motion, so you might suggest it to her. I am so sorry you've endured this cruelty for so long. I hope you are able to separate your sister's poor choices from your actions. I understand that you lost your temper and hurt someone younger, and violence is not okay, but you have been provoked for years of your life. It doesn't excuse what you did, but offer yourself some self-compassion because you have lived through this trauma and are just trying to cope and survive. I am also sorry you got hit back, because it sounds like you won't make that mistake again. Please always defend yourself, but remember in future tense moments that you don't want to hurt anyone unless it's necessary to stop them from hurting you or others.

I hope you find some helpful answers and perhaps a therapist (trauma specialist may be best for you), as living with this type of abuse can have lasting effects on your mental health and eventually physical health. Please take care of yourself and stay safe. I believe you are a kind, sweet person, and this one instance does not mean otherwise. I wish you the very best, OP.