This is heart=wrenching. Condolences.
Yes, 5 years ago my mother died. I was her attorney in fact and am a trustee.
It's very common when the loss first occurs to only remember the good stuff...even if the person was abusive it might be put to the back at first. But as you grieve, reality sets in and helps you realize that she was human and did have her faults, as you said. It helps to allow those memories in, too, as it eases the hurt some.
But still...she was your mother...and what will raise it's head is your anger and grief that now that she is gone there is no chance for you and her to have a wonderful mother-daughter relationship (as if that would ever change or occur anyway, we tend to forget that). It is what it is.
Allow yourself to grieve however it is you need to. Everyone grieves differently but we all tend to go through the 5 "stages" of grief. I don't like to use the word stages because it makes it seem like first you do this, then you feel that...and grief isn't like that at all... you can feel abandoned and angry and guilty all at the same time.
Just remember you're grieving...and don't beat yourself up for any memories or feelings you might entertain for a while okay?