It's sort of the usual story, I was working on something, misclicked to accidentally close it then unthinkingly hit the button to close and not save the file. I really don't want to redraw everything I had, especially because I don't have any old drafts or even any thumbnails or anything to work off of. I know it autosaves, or at least it used to. I've only recently upgraded to a newer version of Krita, but if there's any copy of it left I have no idea where to recover it. If it doesn't, I'm wondering if there's any way to get it back. Needless to say, I've already googled to see if I could find anything that might help, but the only things that came up were unhelpful posts, programs that don't recover .kra files or programs that I don't understand how to use.
Is there anything I can do? Am I completely screwed? Should I just lay down and die?
Help.

If there's an autosave, it's in the same location as your file was, and ends with a .kra~ extension. If you really deleted the file instead of moving into the Trash, and there's no .kra~, you're pretty well sunk, I'm afraid.

I keep my files in Dropbox, so I can use Dropbox' history function, which can recover deleted files for some time, but Windows nor macOS nor Linux do that locally...

There are specialized companies that can sometimes recover a file that has been deleted, but it's very hit and miss and depends on whether there has been any chance that the location the file used to be has been overwritten. It is also hugely expensive.

For the future, maybe check out the incremental save or incremental backup feature, which either saves your file with a new number every time you save, or saves a numbered backup. It clutters your working location, but it has saved my bacon quite a few times.

@boudwijn

Note: If you have autosave enabled, it does produce a regularly updated autosave file; this then gets converted to the .kra~ file if you do a normal Save. However, if you do an accidental Quit followed by a careless 'No', then the autosave file is deleted and no .kra~ file is produced.

It's a good idea to do a frequent Save or a frequent Save Incremental Version. You can always delete the early incremental ones when you've finished and are confident that all is well.