Disconnected

I was adopted by my parents when I was less than two weeks old. That's what I was told anyway. I have a non-bio brother who was also adopted, he's 6 years older than me. I've never truly felt connected to either of my parents or him and it's been a big struggle for me as of late, a dark struggle. Dad died in 2012 from cancer and Mom is in her mid-70's. Time has ran out and they both themselves came from pretty (physical and mental) dysfunctional families themselves. Dad was raised on a farm with an abusive Father. My mom came from a big family with severe mental illness between her Mother and Father. I've always been a sensitive person and I just never matched how they are. They never discussed feelings or knew how to comfort, they themselves weren't happy in their marriage. My brother is a bad alcoholic and I've dealt with that since I was 12 or so. I've been punched, pushed and knocked down too many times to count by him and similar violence from my Dad. My Mom has told me stories about my birth Mom, but it seems like the woman was pretty young and fucked up. I turn 40 next year and I just feel hopelessly lost with no compass. I am trying to match my experiences with research about issues relating to my trauma's. I don't know really where to go or how to start, I just want to see if some of this stuff can align so I can make sense of it before it's too late. I suffer from depression and am in a very dark place right now. I don't exactly even want to be here anymore. It's all just pain, all the time.