Why did specific text disappeared throughout my file?

I'm creating a magazine/booklet in InDesign which has 30 short writings along with graphics.  Some pages contain 2 or 3 writings because they are short.  Each writing has the name of the author in bold above the writing.  Some writings have their own text box and sometimes one text box has more than one writing.  Yesterday the names in bold all disappeared throughout the document, except for one, which remained.  I didn't catch it until I'd already done quite a few other things so I have no idea what I did that made them disappear.  In the Story Editor, it shows that they're still there but they're invisible.  Does anyone have any ideas?