Ok, seems indeed like a corrupted database then, I’m sorry 
Did you copy the file to your computer? Some people managed to repair their database, but it does require some effort and delving into SQL (which I myself have no experience with):
- ByteHamster described the steps to take to (potentially) recover a database.
- A description of the steps that someone took who managed to recover their data by moving data from the corrupted database into a new, clean database, and one extra step for another issue they noticed. (Both the initial and extra step together was confirmed to work by another user. Someone else said it worked a first time round, while a second repair lead to some minor issues.)
- For another person it was just a matter of correctly defining the database type.
- Someone also attempted to repair the database, didn’t manage, but did describe some tools used in the process on a Mac
- Another user shared a link to this article: Android SQLite Database Got Corrupted: Fix It Here! - Technology Blog
- ByteHamster noted that in some cases the database can be recovered relatively easily by SQLite (database) tools.
Would you be up to giving the linked solutions a shot, @neiesc?