Why is my life sad and unfair

Why is life so unfair?

Actually, I don't know why I'm writing this, but I just want to write everything off my heart.
When I was 5 years old, I came to live with my grandparents because my parents couldn't look after me. My mother herself came from a bad background and had pregnancy depression after the birth of my sister.
Everything went down the drain, she hit me, even beat me up with a belt. My father actually a dear person was completely overwhelmed. While my father was working she kicked me out, I was 3-5 years old at the time! And I stayed outside alone without supervision, sometimes I played with the neighbors' children who were older. Often we didn't get enough to eat. My mother then tried to kill herself twice, I still remember how she lay on the floor. Well my father couldn't either. Then I think neighbors reported them to the youth welfare office and my grandparents took my sister and me in because otherwise we would have come to the home, who knows maybe that would have been better.
Well, the time with my grandparents was like that, financially I wasn't missing anything, but every now and then I was beaten and I was afraid of my grandpa. When I was in 5th grade, my grandfather made us rules and if we didn't follow them we would come to the home.
Well, in the one with my grandparents I had a nanny up to the 3rd grade, I loved her very much, even after that time she died of cancer when I was 13.
Well, when I was 14 I went to boarding school and actually had the best time of my life. I also did a lot of crap, smoked, drank, smoked pot. But in the end I got the corner. I did my Abitur, albeit not a good one, completed an apprenticeship well and will now start studying in April.
But I don't know why now everything comes up sometimes. I can't stand people who whine because their parents are divorced ... I always think how good it is for you, I wish I had parents at all. Now you probably think she has. I met my parents 2 years ago, my mum was completely absent - she has brain damage from the pills she used to try to kill herself. You can't have a normal conversation with her, my father is a ready-made person, I'm so sorry. I sometimes feel guilty for not helping him. But I can't, I can't do it, nor is it too much for me. After the meeting I cried because I was so sorry for my parents and I decided not to see them again because it hurts me a lot. Now they write to me sometimes, every time I read a letter from them it's like a stab in the heart ...
Well enough, the worst is also I can't have a boyfriend who has a lovely family, I've noticed, he just can't understand a lot and complains about lapses, something like that leads to arguments and and and ...
By the way, I am female and 22 years old =)