Should I give you a goal to work towards? Or an experience which you enjoy? How about some grand cause? Try to end world hunger. Enjoy reading so much that it's all you want to do. Be the best *insert career* that you can.

...

Doesn't work, huh?

That's because nobody can tell you what your reason for living is. Nobody can determine for you what drives you and keeps you going. These are things people have to find for themselves. Go out and experience different things. Become informed. Find yourself. Some people are practically born knowing what brings them fulfillment and drives them forward. Others have to go through a process of finding it. You just happen to be in the latter group.

I can tell you something which has kept me going in the meantime. The first is that everything changes. If you feel bad, then it won't last forever. Always strive for more and to learn and better yourself, and hopefully a lot of the changes will be positive. Never stop learning and trying new things.

Heh, now that I think about it, I suppose finding something that drives you could be your goal for the moment. Or the experiences of life itself as you search.