How to stop myself from wanting to do drugs?

Up until about 2 or so months ago I had never had more then a few drinks of beer and a cigarette every now and then. I'm 14 and a freshman in high school. It all started with a few shots of vodka. From there I smoked pot and get even more drunk. The weekend after that, I got so drunk I threw up. I became romantically involved with someone while we were intoxicated. I did a lot of dumb **** that weekend. I smoked k2 also. I began abusing sleeping pills. I also got drunk by myself. I continued abusing sleeping pills and have also tripped dramamine 3 times. I started getting drunk with an older friend every friday for 2 weeks, just because I could. I did duster, which was really dangerous and stupid.Plus I've been on xanax, but I don't remember much about that. I got drunk and smoked weed this past weekend. I've gotten drunk 10 or 11 times in all. How much damage have I done to myself? And would I be okay if I stop now? How do I stop? I don't want to ruin my life, I just like feeling happy. But my life isn't what I do while I'm on something. It's what I do when I'm not. I know I need to stop altogether, but I need to know how. Because when opportunity strikes, I can't help myself.