You may have spawned on a new world. Please try this:
1. Go to the Minehut panel, turn your server on
2. Connect to your server, type /worlds and you'll see a list of worlds you have
3. You may see a few worlds listed here. If you see more than one, click on each one and see if you can find your original world that you had lost.
4. If you find it, this is good! Your world files are still available. Keep following these steps to set it back to your default world.
5. Go to the Settings tab in the top right corner of your Minehut panel
6. On the Minehut Panel under settings, look for the box called "Level name"
7. Change the world name to match exactly what it says in-game for your preferred world and save.
8. Restart your server
