It take me some time but finally after reading a lot I recovered all my work thanks to the OneNote cache and reapair tool. Here are the steps to recover lost data: First of all, I made a backup of all the onenote folder from "C:\Users\\AppData\Local\Microsoft\OneNote\15.0\OneNoteOfflineCache_Files" in a zip. You should do this.
Microsoft OneNote is one of the two most-used note-taking applications, and this book will tell you how to use OneNote for school, business, and your A good but very basic guide... ...without some of the user friendly tips e.g. Windows key+N to create a new note, without even having OneNote open.