Hi, I'd like to help you with your problem.
I am so sorry you have to go through this with your mother. From what you said, your mother has attempted to run your life and has prevented you from doing what you wish. Instead she has imposed her wishes on you and as a result you feel depressed and upset about the relationship and her treatment. She singled you out and treated you differently from your siblings as well. You also mentioned abuse by your brother which you felt your mother did not protect you from.
As you described your situation, it is understandable that you are feeling the way you do. Without knowing your mother, it is difficult to know the reasons behind what she acted like towards you, but I can guess that she may have been abused herself and could have witnessed abuse as well. Often, in cases like that, the abused person goes on to abuse their own children or picks one child to heap the abuse on, such as in your case.
You have done a very wise thing for yourself. Removing yourself from the relationship with your mother is healthy. If she is incapable of relating to you in a healthy manner, the only options are to continue to accept the treatment or remove yourself. The fact that you removed yourself shows that you are looking at this in a good way. You are protecting yourself.
Now you are left with all the feelings from the dysfunctional relationship. First, you must understand that none of the actions of your mother or brother are your fault. You are the survivor here. Secondly, do not blame yourself for discontinuing contact with your family. You must take care of yourself. Lastly, it is important that you mourn what should have been a loving relationship with your mother. She was not the mother you deserved and that results in a loss for you. Let yourself feel those feelings.
I highly recommend you see a counselor to work out the abuse from your mother and brother. A counselor can give you much support and guidance to help you move on and gain more self esteem. It is wonderful that you have your husband for support as well. That will go a long way to help you heal.
Keep in mind that you are a survivor. You came through this and have much strength as a result. You are moving in the right direction by asking for help and taking care of yourself. A few books that may help you are Outgrowing the Pain: A Book for and About Adults Abused As Children by Eliana Gil and Adult Children of Abusive Parents: A Healing Program for Those Who Have Been Physically, Sexually, or Emotionally Abused by Steven Farmer. These should help you start on the road to recovery. They are available at Amazon.com or your local library might be able to get them for you.
I hope this has helped,