My pictures are gone!!?

my laptop had been on "stand by" on my desk for about three days because I hadn't needed it. So today, i was messing around on iTunes, and while something was downloading, i thought i would kill time by scrolling through a few of the four years worth of pictures i have on my computer. when i opened "my pictures" only a few of my files were there!! i had organized my pictures by dates and catergory so each file contained numerous sub-files... i immediatley went to the recycling bin and restored all the items in there...but only a few more files reappeared... the majority of my pictures are missing and i cant find them anywhere!! ahhh!! please help! i have tried searching for them, and cant find them anywhere. i never deleted them or even moved them. they just disappeared.