What happened to my pictures?

About thirty minute ago I looked through the pictures I took today on my Nikon D80. Now, I went to go put them on my computer and saw to my horror that they are no longer there on the memory card. What happened, I don't understand how this happened since I JUST looked at them. And, weirdly, only the ones I took today deleted.

I don't know what happened to them, but you can try to recover them with computer software. Stop using that card until you try to recover them so no new data is written on top of the image files.

Wait, don't format or erase anything.
When I was using my D70, I'd create new folders for different events shot during the day. When my brain wasn't working (common occurance) I'd put the memory card into my cardreader and look in the wrong folder.
Go back to your card, and see if you have more than one folder for your photos. Hope that helps.

By mistake you may delete this picture.
contact IT or mobile shop for data recovery of this memory card they will recover all your deleted images.

That sucks. Sorry to hear that. :/ Did you maybe accidentally delete them?