I can understand your feeling hurt and not protected by your mom, but happy is right--she was a victim, herself, and unable to protect you. She may push some of that aside because it's a painful thing for her to have to look at.
I've worked in the DV field for a very long time. Victims of intimate partner violence are sometimes prosecuted or have their children taken away because of their "failure to protect" those children. The thing is, victims in those situations are often literally unable to do anything. They are terrified into a situation where they cannot protect themselves OR their children. They often develop a lot of coping mechanisms that enable them to survive, but not without cost to themselves and their children.
I second dandy's suggestion of counseling/therapy for you. You are the only one you can do anything about, and you're suffering as a result of the violence you witnessed and were victimized by. You could be giving yourself a wonderful gift by doing that and taking responsibility for your own healing.
Hugs, I'm so sorry you had to experience violence in your family.