It's embarrassing how miserable I am and I can't do anything about it

Im a 17F that lives with 3 narcissists, I can't move out because my brother is chronically ill and the guilt of leaving is eating me up alive.

For context, i've basically been on house arrest my entire life, to the point where I wasn't allowed to do anything after school because, according to my mom everything was a waste of time. I'm Indian, so instead I learned how to do every chore known to man and take care of my entire family, including my grandparents who live with us. I don't even know how to explain anything anymore, all I know is that everyday things are getting worse.

For example, every single one of my friends has met my mom, not because I wanted to, but because she insisted. She took me, my brother, and my dad to Macy's over Christmas break so we would have some family time (mind you, this is the only time I left the house for the 9 days we had off) I was wearing baggy jeans, and I had my phone in my back pocket on vibration. we were at Macy's backstage so it was pin-drop silent, and my dad was looking at some shirts while she and my brother were looking at something in another section. She calls me over and I go and I can't find her, so I just go back to my dad, and as I begin to ask him if he saw her, he begins talking about the shirt. Literally two seconds later, she comes yelling at me super loud, asking why in the world i'm not picking up my phone. I didn't feel the vibration, and I began to apologize but she kept yelling and yelling to the point where people started staring at me and walking away. That killed my anxiety, as if it wasn't already bad enough.

It doesn't end there tho, she brings me with her and now were approaching the middle of the store, aka where its the busiest with the most people, but super silent. I'm trying to hold back my tears, and she looks at me and starts yelling at me AGAIN because i'm making a face at her, showing her attitudes. I try to defend myself but now the entire store was looking at me and I just started crying. The whole time she thought I was crying because i couldn't find I jacket I was looking for (???) and didn't understand why I was upset and embarrassed. She also did this one time when I was having a panic attack and she just yelled and hit me.

But i'm at my breaking point now and I have no clue what to do. I barely have any friends, since im not allowed to call or text anyone and my phone is just to call her. She hates the concept of friends, which she told me a few days ago. My parents should be divorced, they hate each other and fight all the time, and my grandparents are the other narcissists. I take care of everyone emotionally and physically. My brother isn't a teen yet and he might be the only reason why im holding back from leaving.

I turn 18 late in the summer so i dont even know how I would do it, I dont have any money because I wasn't allowed to work and i'm from an indian family, so they are very well involved with people who love gossiping and whatever. My parents should be divorced, they fight everyday all the time, yelling like crazy, but they don't because of my brother. I've just never felt this helpless before. I can't remember anything, I can't do anything, I lost everything I was good at. Everyday I watch my friends go out, have fun, hang out with their friends and parents, and i'm here everyday trying to tell myself to make it to tomorrow. I'm not allowed to chose a college I want to go to either, I have to stay nearby. I feel so robbed of my life, I feel like I could have been so good, so much smarter, so much more athletic and artistic. Now i'm just trying to feel my legs after anxious nights of crying.