When you open the editor, the default map is loaded. That’s the reason you see that map.
You can change the default map to open in the editor in the project settings/maps menu.
Probably your map is somewhere in the content paths, you need to look for it. Try using windows, once you know where is you map saved, then you can load it.
Take in consideration thats if you changed the version of the editor, some maps can not be visible. But usually this is when you try to load a map done with a newest version of the editor in an older version. probably not your case.