I deleted video files off harddrive but they still show up in Final Cut?

I'm new to using Final Cut Pro x. I have a 256 SSD and I put about 80GBs of 4k files on my desktop, imported them into Final Cut Pro and began editing.

Eventually, out of nowhere my harddrive was full. When I was done with my video, I rendered it, and then deleted those 80GBs of footage off my desktop. Now I have a 80 GBs more free space, but I still have 160GBs of "Other" showing in my Mac Storage.

What's weird to me is that when I go into Final Cut Pro X and look at my last project, I still see all those clips I deleted! They're still there and playable. How do I get rid of those files? It's like they live in Final Cut now.