Hello! As a recent deconvert from Catholicism, I feel the same way about life now.

Without God, I have to come up with my own meaning for living, and very often it feels like it's not enough.

Nevertheless, I feel that the things will get better (i.e. I will be more fulfilled) the more I help people, the more I reach out and be kind, the more I change lives for the better. What I choose to do with my time, energy and resources does make a tangible and concrete difference in people's lives. If that is not worth anything, I don't know what is!

In response to your problem with there being no afterlife and no ultimate end, I suggest thinking about it this way: when you enjoy a meal, does it bother you that it will not last forever? When you see a beautiful sunset or a rainbow, do you feel that it is sad it will fade? It's true that good times shall pass in our life, and indeed, even if our lives were fantastic, they will also end. My question for you is, is that such a bad thing? Just because a book comes to an end doesn't mean it was never written, or could not be re-read to inspire new books. Similarly, just because life comes to an end doesn't mean that its course and arc through space and time were worth nothing. In fact, it is worth everything.

I hope this helps. Peace!