same here, I've lost interest in socializing for the same reasons. It was fun partying and drinking til I was 25 or so but since then it doesn't do anything for me. Don't like being drunk, don't like being around drunk people, don't like being hangover. Now I don't mind the occasional partying but then it's fun precisely because you only do it once a month or less. I try to organize activities that doesn't involve getting drunk but nobody's interested, and on the off chance they are they won't commit since it involves more planning than buying a carton of beer and head out to the nearest park.
I've lost many friends due to this over the last five years or so. But I'm not sad about it, can't really call someone who's only idea of spending time together involves drinking a friend to be honest.
I used to live abroad a few years ago, we'd go hiking, visit hot springs and have other social events all the time. Funny thing is I happily drank much more then(not that I drank a lot), feels a lot better drinking a few cold ones after a day of hiking than doing the whole club/party thing.
Miss that sorely.