Yeah, I noticed in my late 20s that the world has changed from my childhood. All my childhood sports heroes have retired. New music genres have replaced what I heard on the radio. A lot of my old haunts are still there, but some have been knocked down and replaced. It's an... unsettling feeling when you realize the ground is moving beneath your feet. The best thing you can do is to keep moving yourself (figuratively, not literally). Explore new places, make new hobbies. Fill up your time with new experiences and you won't have as much of a sense of loss.