Hey, there is a very high chance you changed your Level Name, and as soon as your server started after the name change, it generated an entirely new world.
If that's the case, please try the following:
-> Go to the Dashboard (https://minehut.com/dashboard) and click on Edit Server (or Activate if it is hibernating).
-> Now navigate to Settings tab.
-> Check the Level Name. If this is not 'world', change it to 'world' (without the singular quotes of-course).
-> Click on Save and then Restart your server.
-> Now join the server and you should have your original world again.
Note: Minehut has a command called /worlds which allows you to see and teleport across worlds on your server.
In-case you feel lost anytime, always make sure to type /worlds and try clicking on different names that appear.
If this still doesn't fix the problem, make a ticket at https://minehut.com/support/ by clicking on the blue Contact Support button.
They do disappear. Keep in mind, Bukkit servers work differently. They store player's data such as inventory, last location, potion effects, ender chest, etc. inside of the main world folder. Apparently, switching this causes a new world to freshly change everything.