I've lost all info in app notes

After I've recently used the Notes app of my iPhone 5 (iOS 9.0.2), i've lost all the information that I had saved there. I was going to add another note to the app and, after saving it, appeared on screen something about updating the app. I've answered "No at the moment" but the screen went black. When I opened again the app the updating was in process... The notes were all still there but something was wrong. The app closed itself and then... No more notes... I was going to restore my iPhone using iCloud but I came to realize that the app Notes was not included in the copy... Perhaps someone had the same problem? I suppose there is no turning back...

Thanks in advance for your answer and please do forgive me if my english is not so good.