How can i stop destructive behavior before it happens?

hey, i'm really in need of some supportive words. i'm afraid that, with my current life situation, i'm on the brink of addiction. i do some drugs now, and i know that if others, even the most dangerous ones were put in front of me, i would take them with no question. i want to avoid any situation like that and get myself back on track. i want to be healthy physically and mentally. how do i stop this behavior before i hurt myself or others?