Corrupted File

Greetings, I am María.
Out of nowhere, the software closed itself as she was editing a file. The application wouldn't open the file I was working with, and an error message informed me that the file "Is corrupt." I reopened the program, but the problem persisted. Neither the nature nor the scope of the problem are apparent to me. I need to figure out a method to get my long-hour job back since I'm going to lose it entirely if I don't. I am very confused about the issue and would greatly appreciate your assistance. Here is the poster that came to mind; I've attached a picture of it.