Final Cut Pro X Library Failure

For months I've been working (and still am working) on my first ever documentary, I've been following people since a couple of months ago and this is my biggest project so far in my life. I also love making it, so if it would be lost it would tear my world apart. So I was working on this and had opened a library for it (when I started it). The size of the library is now 315 GB. The library contains 1 event, that event contains a couple of different projects. Most of the projects are little scènes that are meant for the actual documentary, and therefore I have a project "documentary" which thus is the main project. But everytime I start up Final Cut Pro X and I want to click on the project "documentary", Final Cut Pro quits, and that didn't happen before. So I can't proceed to work on the project. Someone please tell me how to fix this. It quits everytime over and over. The size of the "CurrentVersion.fcp..." is 260 MB... Maybe it has something to do with that, I don't know. I would appreciate any help. THANKS!