Without knowing your physical environment that well, it's hard to say what's at play that is perhaps contributing to you not being able to interact so well @outlander
From what I have known about it, it seems like a smallish place. That can sometimes bring small mindedness, gossip and lack of judgement.
Sometimes it's not necessarily what you might say, but perhaps how you say (or not say) something. And most of communication between people is non verbal, in your posture, in your expressions, even if you may eye contact or not.
Perhaps you're more mature than others are, so you no longer 'fit' in their world.
My life as a child was mostly in the company of adults, and I felt ackward amongst my peers. I made one or none friends all throughout primary and high school. And as an adult many of my friends were older.
You didn't get to choose your family. And from what I know of them, you are neglected as a daughter but you make a good servant because you don't say no, and you are desperate to seek their approval, which they'll never give you. If you moved away for whatever reason, they would all have to manage without you. You don't have a life of your own, because you feel obligated to serve your family. Everything you do is for others.
I was, and still am to a degree like that. I constant seek approval of others by doing things to please them. But I sometimes say no as well. Politely but firmly.
You're not a screw up lil Sis, nor is there anything wrong with you. You are still finding your place in the world, how you fit into it, and what identity you are. As well as coping with mental illness. That's hard enough on its own when negative thoughts are so prevelant
Your family offers no support at all to, instead they mock attempts that you make to better yourself. They want to tear you down to make themselves feel better.
I hold onto hope that very soon you'll find the right professionals to support and guide you through this difficult time. It will take time for you to get through it all to the other side, but you have great potential. And in time you will take flight and soar.