Welcome aboard GAH. Like the others have said, you aren't alone in this. You absolutely can turn your life around and get yourself better.
I think you need to analyze what your triggers are when you slip. You've got to learn from your past so that you are prepared when those hazards present themselves again... and I promise you they will.
Stay strong and lean on us as much as you can. Stick close to SR and stay as active as you can here as well; that helped me tremendously in the early days.