iMovie Won't Download

Long story short. I made an entire iMovie and tried to export it and it kept giving me a compressor kit error. After speaking with Apple support, they suggested I update my mac - it's a macbook pro 2012. I updated it last night and this morning, I have tried to update iMovie. iMovie won't update, though. It'll start updating and get halfway through and then just stop moving anymore. It's been doing that for hours. So, I tried to stop the download and restart and it does that same thing. I tried to delete the app, but when I hit delete, it never actually deletes. I've tried to movie iMovie to the trash and empty the trash and now my trash has been trying to delete for 20 minutes. Can anyone help resolve this?