My birth mother has rejected me after 20 years

I have known my birth family for over 20 years. My birth father died last year and I was left out of funeral arrangements and the scattering of his ashes. I was so lost as to why this happened and after confronting my birth mother she expressed that I wasn't like her other children. (full blood brother and sister) and that I expected too much of her, she didn't nurse me and didn't feel me. She was very angry. She admitted that all extended family had been told and that no one thought of me. I think what hurts most is the realization that they didn't mean to leave me out, I just wasn't thought of.