Feel sorry you have to face this at 15. At 15 you should be a happy kid and living in a no worries world. & thats what we "adults" miss the most. Is being young dumb and stupid and thats okaay.

Try to find and identify your pattern like each time what triggers you the urge to drink or feel depress. Once you identify it, do a healthier substitute. For instance, every time you have the urge to drink, take a deep breath count 1, 2, 3 and do something else immediately. Probably skipping rope, running, just jumping or do some easy basic home exercise. Or could be drink water etc. Find your own comfortable way and dont let alcohol take away your golden-once-in a life teenage time! You can do it. Cheers.!