NTA.

Oh sweetheart its not easy is it. I am sorry for the loss of your dad and brother, and that you suffered an abusive step-parent. You are not selfish, you are just growing up.

I am a daughter of narcissistic abuse, now in my 50s with my own children not much younger than you. If there was one thing I could do I’d go back and hug my childhood self and tell them its OK, I was not at fault, its nothing I did, I’d also tell myself to work my arse off at school, escape and never look back, build a life. Which is what I did, it just took much longer. But I can’t go back so instead I am doing the next best thing and sending a hug down the years to you with the same advice.

Talk to your local council, you are protected in law and may get accommodation while you complete school. Can a family member help? You are child and there will always be someone who cares, you aren’t as isolated as you think, your mother has just conditioned you to believe that.

Keep talking to your family members but tell your mother as little as possible. Keep it light, day to day stuff like meals, the weather, don’t give the emotional manipulation any oxygen, she is feeding off your reaction and misery so cut off her supply. Try and see it for what it is, she is clinging to you and belittling you so you lack the confidence to leave her, but in doing so she is causing the opposite to happen.

For day to day life while you are planning ahead, try to visualise a thick pane of glass in front of you, nothing she says can penetrate that glass it just bounces off. Its hard at first but gets easier with practice. Having a parent like this can take time to recover from, it might take some counselling when you’re older (I recommend CBT).