I really want my mom and I to be closer, but I don't know how to approach this. How can I improve our relationship?
So many times our parents raise us like their parents raised them. But when parents know better, they can do better. Your mom's personal life might be very dissatisfying to her and she may be taking out her personal sadness and anger on you. You mom needs to learn how to be a better parent and it's not really your job to teach her. You can, however, share your feelings with her about what you need from her in terms of a close bond and being accepted for who you are. Lots of kids have found it easier to write their feelings in a letter to let their parent know how they feel. Though you may be apprehensive about talking to her, I guarantee you that she doesn't want to have a relationship with you based upon fear.
Do you have another family member or adult friend of the family to whom you could talk about your relationship with your mom? Another adult might be able to sensitively advocate for you with your mom. I'd also like you to consider talking with your school counselor about these problems. Consider saying to your mom: "Mom, I can't stand all the tension in our relationship and I know it must hurt you, too. Could we go see a family therapist so we could get help and become close again? I don't want to be frightened to tell you about my life. I just can't tell you things now because I can't keep taking all the hurt and blame. I feel like you never think I'm good enough. Can we go get help, please?"
I know what I'm asking you takes courage. Write her that letter and ask her about going to a therapist with you. Then write me back, okay?