Help! Can't find work-in-progress iMovie file!

I've been working on building an iMovie (10.1.1) demo reel for 2-days using clips from films I've made. But today when I opened iMovie, the work-in-progress file that I'd been assembling is nowhere to be found. The source material/media is available and still loaded into iMovie, but the demo reel file that was automatically saved both days when I closed iMovie, the one I am still working on, I can't find anywhere. Not good. Suggestions?