How can I let go of this anger against my mom?

Lately, I have been realizing that I have so much built up anger for my mom and I can't stand it. 

Just when I think of being in high school and not being able to be in sports or clubs because my mom did not want to drive me anywhere and not being able to go to prom because even though my dad promised he would help me pay for my school debts, my mom did not set anything up and I could not attend and I was turned down for getting my graduation gown until it was almost too late. When I think of the fact that my mom went to college and graduated 4 years ago with my dad paying for her because she said that "she wants to be able to find a job if my dad ever leaves her". Yet she hasn't work or attempted to in 20 years. She will do nothing for her children and sits at home all day in her pajamas watching tv and complaining about cooking for my dad when he gets out of work. He is a hard worker, the hardest worker I have ever seen and she just complains about making him dinner. How she belittles her kids and husband and calls us bad words. I will never call my daughter, or even anyone, what she calls us. I just want advice on how to let go of this anger and how to let go of things that I can NEVER get back like prom, sports, clubs, any high school experiences because I had to work to help pay for my family. Just wish my mother would realize how she is taking advantage of my dad and taking away so many things from me and my siblings that we will never get back.