Please don't try anything again, with the camera, before you have read this and you have all your pictures on the computer. Even when you have deleted all pictures there is a chance you can retrieve them. But saving one other picture can lower this chance. Formatting the card could narrow the chance to almost zero.
Remove the memory card from the camera and place it in a card reader.
Download the free software to recover your files on a memory card:
And run the program.
I hope you did not try anything with the camera or with the card, because with the software you can make the deleted pictures visible again. Please save the pictures to your computer as soon as the program shows them to you.
After you recovered the pictures, you better format the memory card, to make sure no bad sectors are on the card. (Format the card in the camera, not in the PC)