Should i drop out from High School? What should i do?

I don't know what to do anymore, i'm in 11th grade & i only have 10 credits & i need 18 more to graduate. I've been thinking about dropping out, but i really don't want to.. i want to get my diploma. But it's really hard for me to do the work, i can't even concentrate half the time & they give out so much work. if my mom knew about me dropping out, she would go ballistic. I don't wanna take another year of high school after my senior year. i want to become an actor and move to Cali when i turn 19. Since being in the entertainment industry has nothing to do with Math/Science..etc, then why should i even bother getting my diploma?... then again i still need my diploma to work part time. it looks like i'll never get my hands on that piece of paper. Have you guys dropped out of high school?.. should i keep going to school, i am very worried that i might become poor & people might think that i'm dumb... I don't know what to do anymore :/