Notes partially disappeared

Hello,

I’ve been using my iPad to take notes in school for over half a year now. Normally everything was fine - rarely issues with lost data in single notes.

This morning, without me doing anything except starting the notes app, I had a lot of missing data (handwritten texts, scanned documents and photos) in many of my notes that I took over the course of these 6 months. (I really need them to learn for my exams)

I have all of my notes saved to my iCloud.

Do you have any tips on how I can recover the missing data or do you know what happened/what I did wrong?