I feel like such a waste of space.Im 15!!?

Tell mom you would like to sit and talk with her one on one. Tell her how you feel. Voice you concerns, and how sad you are. Regardless of whether you talk to your mom or not, there is no reason for you to harm yourself. Why complain about your mother, if you don't treat yourself any better. Get out of the room and visit your friends, talk to them on the telephone, e-mail them. You are shutting yourself off from other people. You need an outing, even its not a physical outing. Communication with others (friends) is needed badly. Learn how to love and appreciate yourself. There is only one you. Develop your life by being involved in sports, and other activities. Good luck.