Logic Pro is deleting my vocals when I save the project

I recently recorded a song with an electric guitar, vocals, and some software instruments. I always save profusely while I'm recording, so there shouldn't have been an issue with this. I bounced the project and sent it to some friends—everything sounds great, you can hear each instrument and the vocals just fine. Turned off my computer and went to bed. The next day, I open the project, and Logic can't find my vocals. I don't have an external drive, so that's not the problem. I don't mess with files in the project, so don't ask me if I deleted them. I can't find anything online that's a solution to this. It's literally as if Logic didn't like my vocals and just decided to delete them. This has also happened in other projects when I've loaded small stock .WAV files into a track and Logic randomly can't find them.