Mom using me as a cash cow..What do I do?

My mom wont let me get a job because if I work, she wont be able to get child support from my dad,Nor will she be able to get her unemployment checks. I am not understanding her. Even though she gets child support, she never gives me money, even for simple things, like tampons, but she wont let me work. I have to ask my dad for money, and I feel like a burden because he is already getting money taken out of his check for me. I cant even go to the movies with my firends because im always broke. It