Internal memory problem

I went out last night and took some pictures, after about 20 pictures my camera told me that my card was full. i had around 800 pictures on my camera already and when i went to delete some so that the memory card wasent full, i could only see about 7 or 8 pictures i had taken later in the night. this morning i went to upload my pics onto the laptop and used my usb cable to do so, in doing this, the 7 or 8 pics flashed up. i took this out and put my memory card in, the 800+ pics came up but not the 7 or 8 pics. i left it a while. when i tried to upload them again, i couldnt find the 7 or 8 pics, so now all i have is the 800+ ones. is there anyway the 7 or 8 pics could have got removed when i went to view them? i really would like to see those pics so if anyone can help me id really apprechiate that. thank you.