Illustration lost

Hello!

I had to leave my house not to destroy the ipad! I've spent 3h30 working on a project! I didn't get out in that time so the file could be saved. So I started the illustration and once finished I've clicked to go home so the file could be saved. Instead AF, asked me to get some space so it could save the file. I went on deleting apps and photos to get the space. Back to Fresco the file evaporated ALL THE WORK! And I was back 3h30 hours earlier! This is absolutely insane. What just happened?