why cant i let it go

So I got adopted when I was almost two my mother never wanted a thing to do with me my grandma took me in and cared for me till my grandpa passed and had no other choice but to do what she thought was best and to a couple that truly wanted a baby so through out my life I always felt like why me what did a lil precious baby ever do to deserve this and have struggled with it so as the years went on and I got older I was told about being adopted in a very mean and cruel way so from that day on my heart shattered in a million lil pieces and felt betrayed like I was lied to I always felt like I was not loved like my brothers and sisters and was kinda the black sheep my mother that adopted me always reasurred me that even thou I didn't come from her belly I came from her heart and that she always wanted me I feel bad for the hell I out her through from me feeling lost and broken inside so when I was 16 I called my birth mother and I can still remember the sound of her voice and excitement how I waited so many years to hear her so we talked and she promise to call back and never did and a week later she was involved in a head on crash which left her in a coma for a year and her body just shut down and she had to be taken off life support so then my mind questions why again why didn't she call back my uncle she I caused her to face her fears that she had ran from all these years and they smacked her right in the face I hold ALOT of hard feelings towards her I have two half sisters from her and when they were two and one she left them with some guy and never looked back so I guess she never had any want to ever be a mother she had it three times to be a mother you would have through after not wanting me she would have made it right with my sisters but never did so I just have all these feelings bottled up that none from my family can relate and they don't understand why I feel the way I do at time just let the past be the past and move foward which is so easier said than done as for my birth father he said its like were good friends so I have tried to have a bond with him over the years and feel so out of place like I'm a stranger in his home so I'm not going to put forth any effort and just let it be its a two way street and its always me going out of my way so in all of this I hear from time to time how I remind him of my birth mom and I have only heard bad things and want nothing to be like her a selfish un kind caring woman when I had children I want them to feel and know there wanted and loved with every part of me and they are my whole wide world I vowed to give and have my angels feel everything I never had or got to have from my mother be the best mom person wife and friend to all I just want to have some sort of understanding of why and I tell myself I have moved on but I havent if I'm pouring my heart out thanks so much for listening any advice would be great it feels so good to get that off my chest :)