[NickM]

We all die eventually, but if you dedicate your life to something bigger than yourself, then you can feel like your life was for something and that a part of you will live on.

Historically, many people have gotten this sense of "something bigger" from things like kids/church/patriotism/etc. But you don't necessarily need things external things like this. I used to feel a sense of purposelessness like you, but I've gotten a lot of satisfaction from trying to live my life according to a set of higher principles.

What frustrates you in life? If conflict bothers you, try to find ways to foster peace and cooperation between others. If ignorance bothers you, try to find ways to teach others, and spread knowledge that you feel is important. If inequality bothers you, find ways to help effect change in the world. These are just examples; I have my own things I care about, but that's not important, as you might be completely different.

The possibilities are endless, so don't expect to figure out what works for you right away. It takes time to figure out what principles resonate with you, and it's not trivial to create a personal code to live by, but I believe it's totally worth it.