Folder in notes disappeared

Hello,

I was writing in one of my notes and my phone just froze for a moment and the whole folder under which that particular note was stored disappeared.

When I go under the main “Notes” folder I can find that particular note but the 50+ notes that were in the disappeared folder are gone.

I checked the deleted folder and nothing but the notes I deleted on my own.

Few days ago I received a notification that my iCloud storage is getting full but I doubt iCloud would just delete my notes and folder. I have upgraded my storage now.

Please I need those notes I have been writing work related info in there for past 5 years and they are very very important!

Thank you!