Struggling with severe alcoholism/addiction.

I'm a girl in my early 20's who's pretty much on the brink of success. (Just signed with an agency, starting to get media exposure.) After experiencing homelessness and jail time, I feel that I have earned my spot. That being said, I struggle badly with alcoholism and drug addiction. I've been to rehab multiple times. I've been in-and-out of AA/NA for 10 years. Nothing works. Nothing. After completing my last rehab stint, I went back out after 36 days. I just couldn't do it. (Longest sobriety time I've held is 8 months.) It's gotten to the point where I'm actually convincing people I'm clean and sober...and they actually believe me. My tolerance has gotten that high. I just consumed 10 MG of Dilaudid, and polished off a bottle of vodka. Yes, I'm still clearheaded and feel sick. NOTHING WORKS. What do I do? I feel helpless. I promised myself (and a close friend who took notice) that I'll check into rehab AGAIN, if I don't land an important audition coming up. I need honesty and advice.