My advice: Don't think about life ending, think about the opportunity to do as much as you can with the time you have living. You can't do jack stuff when you're dead, so live it up while you're alive.
I have a pretty up-beat look on life, and I can never manage to be sad for more than a few minutes, because something good is always ahead. Maybe it's just my life in particular, but life is pretty damn awesome.
You can all say life is so bad for so many reasons, but they can all be countered by a good outlook. So my advice, I guess, is to always look up and if things are looking too good at the present, cheer yourself up by looking forward to the future, but don't get lost there. At times it's best to live in the present, and take life as it comes, knowing that if one day is bad the next will probably be pretty good.
There's always light at the end, and as Magick Mage says "No moment is a waste as long as it's filled with love." or something along those lines. Cheer up guys!