I think counseling would be best first, the counselor can help you find a more productive way of telling your mother how she has hurt you in the past. You seem to have too many issues with your mother to talk to her without knowing what you want to say because then your brain tries to say everything at once. You want to plan out what you want say so that your mother can know exactly what it was that she did that made your relationship so strained, she probably already knows but has put it in the back of her mind so not to feel the guilt and to what extent the pain is. Parents are suppose to be our protector and our rock and your mother wasn't that for you and that is why you still have so many issues with her, you don't feel she had your best interest at heart and there for made you have issues and do some things wrong in your adult life. Counseling would have been even better as you were younger so that this could have happened a long time ago but it's never too late. Do the counseling first then secondly write down everything you want to say to your mother and even study it so that you don't fumble over your words because of your anger or hurt.Then make plans to sit your mother down and talk things through one thing you have to do is look at your part if any in the break down of the relationship also if there isn't anything you did then make sure you know exactly what she did to you and your children and tell her how you felt about her doing it.
It's good to know you have a support system and if you need my help again please don't hesitate to ask for me by name I will be more than happy to help again. Good Luck!