Premiere Deleted Part of My Sequence

I have been editing footage from a live music event. I edited thru the first song, and then before bed decided to sync up the rest of my footage so tomorrow would be easier.

After syncing everything in the timeline, I went back to the beginning (Ctrl+i) and was confused because the entire first song is now gone. As is all of my work. Hours of work. I want to smash my computer into bits.

Autosaves are no help. Inexplicably the oldest autosave is from after over two hours after I started working. I had saved the project before of course, but not as a copy. This has never happened to me before and I am flabbergasted.

Can someone please help me? Or was my time just wasted in such a frustrating way I can't even begin to express it.