To be honest, I don't know how you should go about turning your life around, but it's certainly not impossible. Things I have considered to beat my alcoholism have included moving to a new town or country, and cutting ties with all the people who you feel dont stimulate you to turn yourself around.
Sometimes a totally fresh start in terms of company, relationships and scenery can go a long way to help you make a fresh start with your lifestyle.
Of course, it's never as easy as it sounRAB.
For inspiration, if you need any, I'd reccommend you read "A Million Little Peices" by James Frey, which covers many of the problems you describe. The book is an autobiography of the author's trip though rehab for drug and alcohol dependence. It took a lot of stick since it came out that some of the details were "erabellished" but it's a motivating and inspirational read. It helped me out no end.
