This makes it a bit harder to get people to read cause I'm not yet a very active member...but here goes.
Just to chip in my 2 cents, my old man died not too long ago, gf stabbed me in the back in the most of emotional situations (obviously not literally), lost pretty much all my mates, my mother now is 'feeling her age', threats, fucked up my education etc.
Not great stuff, but that's just the surface of what goes on in our lives. The bunch of guys crackin jokes at your expense may have their own way of coping with their stresses - but we are individuals who are unique because not one of us thinks the same way, in addition to other characteristics. What helps others might not apply to someone else.
I know for me, I took time off everything and just sat on my ass. Reflecting on what had happened, what this meant, what is gonna happen, etc. Really letting it hit hard, because if you fight it it'll just go on longer, and even worse it'll build up. Why keep a strong face - it's wasted energy to maintain this stupid macho-esque stereotype that males are bold and tough and nothing can phase them, that we are tanks and we can walk through fire and ice and still be wanting more bullshit.
What I've come to, is that life/love/anything is really like a rollercoaster ride. It has its highs and lows, but...remember after every low there is a high. Question that phases everyone is how long it'll be until the high does come. (if you got the image of drug use that wasn't what I was after lol)
Cruise through the highs, fight through the lows. No one said you had to do it alone - getting back up to the top can involve talking to others, and in serious cases to medical professionals. If you fall, take a good hard look at the way you've already come and the hardships you've had to experience to get to the point where you are. It'll be pointless to let it all go to waste. I don't know you personally but I get the impression that you are who you are for something a bit more than "booze, burnouts, sluts, etc". Like I said, something that works for a particular person may not work for another.
EDIT: after re-reading your first post...yeah I rkn you are after something more than mediocrity (sp?).
You never know what life will throw at ya next, but you can still take time out to get yourself together again in between.
Happiness...is hard to identify. How to truly be happy - doubt anyone can come up with a response that'll help you in that regard.
Only person who can find out how to truly be happy is you. Explore, communicate, create, whatever. I reckon some of us when we really think hard will realise we aren't as happy as we can be at this stage in our lives. Like the saying goes "Money won't hold you at night" (paraphrased coz I'm an idiot and can't remember the proper saying

). Why settle for second best? More importantly, why let the negatives interfere with your search for happiness?
Hell, I haven't found it. At my age it shouldn't even be crossing my mind, I should be into illegal and unlicensed racing, eccies, random sex and wagging school, getting tattoos, smoking pot, passing out at mass rave parties, etc. What makes me happy at the moment? To be completely honest, I don't even know.
Instead, I'm going to uni in advance, I illegally drive up to Coles to get stuff for breakfast or stuff to cook dinner and nowhere else (I'm on my Ls still), I get into serious, emotional relationships...I validate my metcards for fucks sake! (I do have fun though - that's a different story..)
Take the stuff I've said loosely, but if it helps, maybe even to get some perspective then I'm glad. If not, then oh well. When ya get through it, at least you'll be able to tell yourself you made it.
It all boils down to this and other people have said it: live through it and cry if you wanna cry/break stuff/whatever to let it out, tomorrow is a new day. Make of it what you will.
Or just disregard what I've said, after all it's just my 2 cents.

(why are all my posts essay length!?!? argh..)