Bookmarks deleted

I was signed out of the Gospel library app, and when I signed back in my bookmarks were nowhere to be found. I use the bookmark function to remind myself of questions while reading, so it is important to find them. Is there a way to get these back?

Are you using the iOS, Android, or Windows version of the Gospel Library app?

I am using the Android version of the app

I use the gospel library app on an android phone.