Dan, I am very lucky that I had only one day in my 42 years when life did not seem worth living. I had little ones to take care of by then, and I stuck around for their sake. There is nothing like being in charge of a new life to make one hope again. You have not been around long enough to know if life is worthwhile or not. During my generation, I feared that we would be nuked by the russkies. Or by the US by mistake trying to stop the russkies. In the seventies, I didn't bother to get a driver's licence, because we all knew there would be no oil left by the eighties. I lived to see the Berlin Wall come down. I cried. Even though that wall was half a world away, it was a burden on my soul.
I found out that the prophets of doom are often wrong. There is something beautiful about simple living. The network of friends and loved ones, watching flowers and children grow. Perhaps, Dan, if you did less living in your head (worrying about things) and more living outside (meeting people) you would find more meaning in life.