lagirl,
you will get much help here. i can share my experience with alcohol. i started at 16 and increased use until 36 years old. i wish i had your insight at any time during my drinking career. i didnt get dui's, or lose my job. i was forced into rehab while i was in the Army. Luckily I got it, or else I would have been discharged as a rehab failure.
The guilt and shame were always there for me too, but I kept drinking anyway.
If you try to stop and cant, there are resources to help you. Have you talked to a doctor and been honest with your problem? Have you been to any meetings? I went to AA, and when I started looking at the similarites between us and not the differences (oh, i had that ego too, i am NOT like these people), my ears opened up to the knowledge, experience, strength and hope of living a new life.
I hope you keep posting and reading here.