Mentally depressed because of family

I m Kohinoor Barbhuiya from silchar,assam. I m18yrs old. I m the elder daughter of the family. I have more younger two siblings. I usually leave all those matters by saying chodho yaar jaane do. And its being now too much that i used to stay so distrbed. I can't concentrate on studies only it comes in my mind to leave to this house and to go. In 2015 april, My parents they got separated for their own problems and mostly my father's behaviour is worst with my mother and with us since till now. He used to raise his hand on my mom most of the time. And used to disrespect her. I used to see and still got to keep quiet because my mom used to say that if she leaves home with us then no one is there to feed us, to provide us education and other needs. My dad never allowed my mom before to work for her proffesion. So she was jst a normal housewife. Since i didn't understand much at that time. And keep quiet. Aftr my mom and dad separation i broke down completely. I was mentally disturbed since that time to till now. My dad is not much free to us. He just don't care like how mom used to do. We were sent hostel to study there in another state (tripura) at 2016. And in 2018, during August. My mom was going through an operation. Kyu ki maa ke peth mein stone ho gaya tha. And we was in Tripura that time. She called me and she said that my dad got married with another woman. I was not believing Her word. Even he did not say us that he got married with another woman. After some days of month august, he brought that women in our rent house in that place where we are living. at that time I believed that my mum was right and I was so much disturbed so much broken that he lied to us about this. Which is not accepted and we thought she will be good but slowly slowly she shows her real colours. she used to say bad about us in behind. And some of those words even our father believed and he scolded as for that. we three siblings we were just broken even we just one to leave the house and wanted to go. The girl doesn't care about us and she just know her needs. My dad he doesn't care about that he doesn't listen to us his ego is important his attitude is important. We want to go and stay with our mum. Slowly slowly the time changes this mentality pressure became so more that even can't concentrate on my studies. On 2020 my dad and my mum officially there took divorce. 2018 another marriage of my dad that time did not take divorce from my mum he married and then he took divorce. He don't usually allow us to go and to meet with my mum. I am bound to say but I don't want to live with my father due no income of ours and my mom as we are living with our father. we don't want to live with him. We don't have mental peace we don't have freedom we don't get any care we are just living by ourselves in a house where it is like a jail. where there is no feelings for us. I want that my mum should get the custody of ours. I was depressed and I am still depressed. Please help anyone.