I guess you've been working in the RMD tool (not chibipaint, not canvasdraw).
I had the same thing in the beginning so I always saved the drawing to my computer. That's the safest way. I don't use the tool anymore ono
I was working on a drawing, which I had put a lot of work in, when the page suddenly wouldn't work properly. I don't really know what was going on, but I saved the drawing into a folder and restarted internet. When I logged into RMD again and was about to open the file again I got this message saying "No drawing previously saved in that folder"
SO NOW I'VE LOST ALL MY WORK.
It wont work when I click "Load your last Autosave" either, because the same message pops up.