iMovie won't stop "Importing files" and will not let me exit the application, force quit, or restart my computer because its "finishing tasks"

I was attempting to create an iMovie but had so many issues I wanted to force quit the application. It wouldn't allow me to force quit because it was finishing other tasks, and now I cannot shut down my computer because of it. There is a little pie chart in the upper right corner of the iMovie screen on my MacBook, but it doesn't seem to get past an eighth filled. Please help!!