Saved Project vanished

Hi all. I just saved a project, multiple times while sampling in vinyl. I named the project “Project 28” when I created it. I sampled 10 records, and assigned each sample to a pad on Bank A and B. After the final save, I noticed the audio output had stopped coming out when I went to play the pads - though it was fine before. So I saved the project again. Switched off the unit. Switched it on again - and my project is not there. I have tried saving another new project (project 29) and it shows up. Anyone have any idea why this might have happened ? I spent quite a long time choosing samples so am hoping that they are in there somewhere - but I have checked the other folders and cant see it anywhere. This is the first time this has happened.

Actually it ended up in Project 27, as project 28! Not sure how or why though!!