Hey, I'm very sorry your progress was lost! This is unfortunately something that happens sometimes with browser saves. I'll look into maybe creating something like a cloud save system, but I would have to ensure it doesn't end up being really expensive for me as the save size and bandwidth from all players adds up.
In the meantime, you can always Export your save from the Game Menu regularly and store it in a safe location, then Import it later.
But I know that doesn't help you now. Unfortunately, I have no way to recover your exact save. However, I can give you a save file with a lot of resources that could help you rebuild. I've made such a file for Evan before, https://florianvanstrien.nl/files/TheFinalEarth/saveWithLotsOfResources.sav (right click/hold -> save as, then import it in the game with the Import... option in the game menu). If you were playing another scenario/had other progress or need help just let me know.