Well, SnS, I think the reason so few people have replied to you is because they consider an underage person being unable to drink a GOOD thing.
I will tell you this. 5 years ago I got deathly sick off cheap wine. To this day I can not drink anything but top shelf alcohol. Which means, no beer, no cheap wine, nada. I think the reason may be because the top shelf alcohol goes through intensive refinement processes which filter out a lot of the impurities found in the other stuff. The funny thing is, I can't tell the good stuff from the cheap stuff if it's mixed in something, like Orange juice...but my stomach knows the difference. If I take a few sips I immediately get the swirly sick feeling which tells me that I have to stop or regret it.
So...unfortunately I don't know what to tell you. I've never gotten over the affliction. I don't regret it, though. If you're going to drink, stop drinking that swill and at least do it right. Yes, it's expensive, but you don't need to drink as much. Although, in truth, I would recommend giving up using alcohol to relax in the evenings altogether and switch to something less harmful to your young body...like yoga, or meditation.
Actually, meditation may help with some of your other problems as well. It can help calm you and relax you, and you can use your sessions to help sooth your feelings of dissatisfaction with your sports career and bring forth a positive outlook on your situation.
Why not give it a try?
Here's a link that may help...
http://home.att.net/~meditation/MeditationHandbook.html