Is your DCIM folder on the device or an SD? If it's on an SD Recuvva should be able to recover it by downloading the program on your PC and connecting your device to your PC as readable memory or with a card reader. If it was internal memory, I'm not sure if it will work, but Recuvva is freeware and it couldn't hurt to try. In the meantime, if you can avoid it, I wouldn't take anymore pics or videos or if you can't avoid it, change the save location to whichever you aren't using. Internal if you're using external, external if you're using internal.
I've had about 87% success rate with Recuvva. The one time I needed something and it didn't work for me I was able to Google "programs like recuvva" and found a list of about 10 other programs and one of those worked for me. I'd be wherry of paying for a program that says it can recover from devices without checking reviews from sources that didn't include links to or ads for the same app. Remember reviews can be faked.