Help me! Mother and daughter crisis!?

Now I love my mom - a lot, but she and I don't get along most of the time. She says I'm too disrespectful. I am - but I don't mean to be. I just snap most of the time and she has little patience. She's a wonderful mother and I want to make her proud of me, but I cannot do that if we are constantly bickering most of the time. I don't mean to say the things I do and I come off as a *****, but I seriously do not mean to. I need to improve on being a good respectful daughter. But how can I apologize for what I did today? Today she got so mad at me, that she cried and yelled, "You're the worst daughter ever ever! I hate you! And as far as I'm concerned, I don't have a daughter anymore! So run away if you want! Go kill yourself! I don't care! You're not my burden anymore!" This really upset and put me into a fitful of tears. I'm dead to my mother! I just.....I just cannot take it. I want to apologize, to work on my flaws to become a better daughter. I'm ashamed at this. I really want to be a good daughter. I want to apologize and not talk out of my like I usually do. I need some helpful advice from someone who understands?