Well, at least your mother doesn't deny what happened to you. My mother always would deny it and if my father was around, he would take her side---sometimes he'd take me aside and tell me not to bring up the subject at all! Since your mother doesn't deny what happened, have you considered just laying it all out on the table? I don't know what your mother's personality is like but maybe by confronting her, she may acknowledge it all beyond "I did the best I could". This is something I wish I could have done with my mother---maybe it would have brought me some (to use that often bandied about word) closure.
All I know is that at some point you will have to find a way to deal with it all. My brothers and I have our share of problems that I know can be traced back to how we were treated as kids. I struggle with a weight problem and know I have a lot of anger inside me that I don't know what to do with. My friend tells me that it shows up as physical ailments. I have IBS--my friend tells me that when I come to terms with all these feelings, the weight and physical problems will subside. I don't know if this is true but I'm willing to work on it. One of my brothers is depressed and drinks and smokes way too much. The other one seems to be perpetually angry. Both of them verbally abuse their own kids, even though I've pointed out that we were treated that way and they shouldn't treat their kids like that.
In the long run, I think that you, too, will eventually work on your feelings. I can relate to feeling angry when you think about what happened. While, I don't think about it all the time, sometimes something will trigger a memory and the feelings arise.