new to this

Hi all. Thought I'd give this a shot, though I'm not too sure how it'll work. So, like everyone else, I am the daughter of a recovering-ish alcoholic father. I am the oldest daughter, and throughout the past probably 12 years of my life, the bulk of my adolescence, having my dad in the home had been hell. Even though I was young, and still am, so much of the responsibility I felt was put on me, like I had to take care of my younger sister and mum, and even my dad. He's been put through rehab multiple times, kicked out of our house and brought back in, and everything in between because of his addiction. I was put through family therapy when I was younger but it never did much for me then. Anyways, I've gone off to university and for the past two years I was finally able to breathe, living out on my own, though I still have felt this constant guilt about leaving them all back home going through that. Now I am back for the holidays, and finally my parents are separated, my Dad is sober for now and living on his own. Because he's sober recently, and from being away for so long, I am feeling a new sort of guilt and sadness for leaving him alone. I try to reach out, but there's this whole mix of feelings of anger and trust issues, but also guilt and my heart breaks that he is lonely during this time of year. I try talking about all this with my mum, but she and my sister are nowhere near as forgiving as me and don't feel the same I do. I'm not sure how to split my time, or make things right...I'm also struggling how to cope with the fact that I myself can't just make things right. So anyways, I didn't know where else to go with this and I felt like a forum could be an okay place to start. I appreciate any advice.