I had a short period like that, well not like that, but similar. Currently 30. That's why I've always said - do whatever you wantr, but no alcohol or narcotics. They fuck you up in many ways, your thinking, your moods, your motivational centers, etc... that's the worst thing. I've stayed away from that shit and while I have down times here and there, overall life seems better and better with each passing day, less worries, less stress, I'm more calm than ever before, it just takes time to get over these feelings, esp. if you're an intelligent person - you WILL find out tat life is indeed - pointless. Many, as someone said, desperately marry and have kids (poor kids) so they have something to do, on the long run most of them come back to the same state after it wears off or kids turn out to be an additional stress/trouble or financial burden. Some find a meaning tho', depends on what kind of a person you are.
I can't give advices as I'm an egoistical, hedonistic, atheistic asshole, I can only tell you what makes me tick (as you've asked): each day I wake up with a goal to improve myself, each day I have my focus on my goals, each day I'm looking for something positive to happen (guess what - it does), BUT - I do not take life seriously at all, I couldn't care less if it ends tomorrow, I"m living fully, no regrets, I couldn't care if any of my areas of life fail, I"ll get over it, no biggie (death is worst that can happen afterall) and while in the process of all that for me it's like a survival game, like a Lineage, I'm trying to level up by the standarts of this reality that we live in, in other words - I try to become as strong (in every way possible) as it is possible, financially, psichologically, physically, I get a kick out of that, I get a kick watching my enemies fail, I get a kick knowing that they are aware that I'm above them, I simply enjoy this animalistic pleasure when and while I can. Im probably lucky to be born in a strong family that taught me how to be strong so yeah... most of the time I'm feeling happy. One more time - ditch alco and narco, for ever, it's not too late for you, I really can't emphasize this enough, you will thank yourself many, many times, while watching how your friends and non-friends are crumbling down around you just beause of that shit/a way to seek for relief (it;s weakness, weakness is death, death = not very happy).
If I'd give an advice (I'm not someone who stands besides life, so I can just tell my experience), I'd say - have goals, big goals, even if it's dificult to see the point at first, once you get it rolling - you'll wake up with a heart full of fire each and every morning ready to go and make it happen. Oh, and don't ever sweat relathuionships/ïssues" with females, I personally dont'have none (and find it ridiculously easy now to get poon, easier than ever), but I see lots of guys stressing over it. STOP and earn money, you will feel at ease, everyone arpound you will feel that, females too, and it's very easy to get them when you just don't give a shit, because you know that at the worst you'll be able to buy sex, it's liberating.