you know Baker, in a sense i think you should say good bye forever to something.

Part of your suffering is that you superimposed the mother you always wanted to the person that your mother really IS.
I want you to know that wanting a good mother is natural, that you deserved a good mother, probably someone much more like you.

But your real mother could never fulfill your dreams: she is a different person, no matter how hard you tried to pull her or to attach your lovely dreams to her figure.

You are suffering so much just because that little girl, long time ago, was too forlorn to think: all right these are the things i need from my mother but i am not getting them from this person. Let's turn somewhere else.
You were too young, not strong enough to think that.
So you continued to dream on a good mother looking at your mother: no way.
You know that, now.

So a first step out of suffering is dividing your real mother from the one you wanted, needed and deserved.
Take some paper. Write on the left part all the things you want(ed) from a good mother. All of them. Be precise. Don't let nothing out.
Then take some other paper (it's better if you don't read what's written on the left part, while writing the right part) and write what is your mother. All her applications of the idea of mother.
You better do this exercise 2 different days, so your mind is concentrating only on the wishes, for the left part, and on reality for the right part.

I hope you won't see your mother anymore with those hungry looks of expectations of things that would never come from the person you were born from. Not because it is her fault, your fault or my fault, but simply because she is a totally different person from your expectations.
You applied the magic thinking, like all babies: if i really want this with all my heart, my mum will became what i want.
No.

You must really separate your desires of a mother from the reality of your mother.
Once done that (again, help is needed and recommended to be supported in the process) you may look at the person you have called Mum for all of your life, but your eyes will not be burdened with all expectations that never came true. You would look at her, for what she really is. You will learn to have fun with her, where possible, stay away from her, when necessary. But for the first time in your life you will really look at your real mother and say "ah! that's who you are"