Sound Lost in Track on GB

Hi there, I'm in major need of some help. I recorded over 700 measures of real instrument music on GB (latest edition). As I went back, I cut what I didn't want. After some time, a message came up. Something about the real instrument tracks. But I don't remember exactly what it said. After that I didn't get any audio from it. I later realized that the sound had died on my laptop some how (it's a 13" Macbook Pro). I restarted and I had sound again, but still no sound in that file. I have no idea what to do next.

I opened a new GB project and it's not even recording sound.