It's too late for this now, but if you catch it right away, reach around and turn your computer off. Do NOT do a Special/Shut Down, just turn it off, even if you have to unplug it. Wait a few seconds then turn it back on. Your files may still be in the trash.
I've done this a couple times with wise guy students who throw away an incomplete file that they didn't want me to see, and then they claimed it was an accident. Imagine their dismay when I shut their computer down and bring it back up and pull the file out of the trash. :-)