My project has disappeared

I copied my project to my external hard drive (my iPod hard drive) and after I had ejected my iPod, I went back to play the movie in iMovie and it was playing up (some pictures were not appearing - just a black background) and then I closed iMovie and opened it again. Then my entire project had dissapeared and I tried going back to the folder where the project was stored and I tried opening it, but iMovie just came to the front and nothing else happened. please help!