Good news! It turned out that when I deleted all the media files from my desktop, that was what caused my audio files in my project to go offline. For some strange reason, when I checked System Settings, all the media files was pointed at my desktop and not at my FCP Documents file. I have since resetted the System Settings and I also batch captured all the clips that went offline. Everything is back to where it was before. Many thanks to everyone out here who helped me! 🙂