Lost iPhoto Pictures

Hi. I got back from my holiday and I had taken around 1500 photos. I uploaded them to iPhoto on my mac and deleted them from my camera. I was looking through my photos then iPhoto crashed. When I opened iPhoto back up the pictures were just grey boxes. When I clicked on a box a triangle with an exclamation came up. I took it to apple and the guy there didn't know much and he told me to look in the trash and the masters. The iPhoto trash didn't have any of my picture and I was only able to recover about 180 pictures. Please help if you can! Thanks.