Unable to open and repair PDF

HELP!!! Not so funny when all your notes from university are lost!

I already tried:

- to update the Adobe Acrobat Reader DC

- help ->  repair installation

- open the document with several different PDF readers

- several online repair services for PDF

- free software for repairing PDF

- previous data isn't available

- to copy the document into another path

I need to learn for my finals so please someone help me?!?!?!