Recovering lost video?

I took an adorable video of my daughter laughing on my nikon d5000. This was a few weeks ago, I had put the SD card into my computer and uploaded it to Facebook for friends and family to see. I can't find it on my computer and I don't remember saving it. I have no idea how to retrieve it, and I don't know how to save the video off Facebook or if that's even possible. Some please help.

You can search your full computer for all your video files and see where it shows up.

Usually it is prudent to always copy All the image files from your memory card to your computer at the end of each shooting day. Then once you know they are safely on the computer and where they are, format the memory card using the format feature on the camera

If you can't find the video file on your computer and have not used the card since moving the video to facebook, you can use a commercial image and video recovery program like Lexar's Rescue4

My pictures
my videos
or it is still on the sd card