I've found the best cure for nostalgia is filling your time with new experiences, especially with good company. Maybe try seeking out some stuff that's outside of your regular comfort zone.
one option is to take inspo from others. think of fictional characters or real people who you think of as fun or cool or different from you in an interesting way? what stands out to you about them? and try to model that. another option is to slightly change hobbies/habits you already have. walk a different path to work, paint in a different color, sit in a new coffee shop. perspective can offer you something βdifferentβ. one last thought is to make a new friend. talking to new people can help you see the world a different way.