I have lost photos on my memory disc. Is there a way i can recover them?

So, today is my 8th grade graduation, and i was taking pictures. First the pictures were on the camera. And then when i turned it back on, all the pictures that i took that day were gone. So i know that they didn't get deleted. I need help. i already tried googling, but that didn't help they kept giving me links that i had to pay for... So any suggestions??