Document lost after unrolling

Today I just set a new project and arranged for about 5 hours. I unrolled the music score and did a lot of composing and recomposing, with pushing ctrl+s every few notes. But the unrolled document still lost when I reopen the file, only the notes before unrolling left. The score lost was so important for me and hopfully you could solve this problem as soon as possible, and I badly wish you could helpme to refind my lost score. Thank you a lot!!!