Canvas deleted the notes on my pdfs

[lfmantic]

I was writing notes on instructor provided pdfs last night. All of a sudden, canvas spazzed out and when I logged back in, it had deleted the majority of the notes I wrote on my pdf as well as previous pdfs's notes from weeks ago. I've already transferred my notes over but how do I prevent this from happening again and is there any way to recover the notes that were deleted. 

[KristinL]

Hi @lfmantic  -  Were you working with the Canvas Student app?

[emmagrif]

I know I wasn't originally the one who asked this question, but yes, I was using the student app on my tablet while using a stylus to write on my PDFs in Canvas. If there is any way possible to restore what I've lost, I really need it. It had all of my music theory notes on it.

[h18_6yyya]

Hi how can i get it back? All the notes at class is inside, I really feel hopeless now, next week is final exam....