Why do I get bitter and envious when I see girls and women bonding with their mothers? Mother/daughter time

When I was five, my mom decided that she wanted her own life and not wanting to be a mom anymore so she abandoned us. I don't remember having a mother/daughter bonding. My dad would ask when is mommy coming home. Mom broke promises, never keeps her word, she stood me up twice and never ever apologized or felt bad for what she did. She just said, "Welp I forgot." And didn't feel awful. My friends and family told me to move on and I don't need her. It hurts seeing moms and daughters, even my best friend and her mom laughing and I never had that. Why does my friends get to have their mothers around when mine isn't?! It isn't fair. Why did my mom have to leave?! My mom told me on a text two weeks ago, "Listen I don't wanna be brutal but I don't see you or your brothers much as my children anymore. You're no longer my daughter and let's be honest, I haven't been around. You and your brothers are no longer my children. Talk to ya....whenever." my heart shattered when she said that. Why no why?!