Is it okay for someone like me to not really have a sense of humor?

People say I should be laughing and enjoying my life because I’m young, but is it weird that I don’t? I mean I laugh like a normal person, but nothing seems to hit my funny bone lately. I just keep dwelling on the past and I’m so engulfed by my own thoughts worries, and hurt that I only here “blah blah blah, get it?” and everyone laughs and I feel out of the loop. I don’t want to hear things that make me happy I guess? I have no idea… suggestions