My pages docs vanished and got replaced with dupes of other pages.

I write my notes for my college lectures on Pages. Recently, I went back to my notes folder, and a bunch of pages of notes were missing. I titled each one with the date, so, say I had a lecture on March seventh, the document would have that in the title. Instead of finding a March seventh doc (example,) I was instead greeted by three copies of January twenty-eighth and two copies of February sixteenth. I checked everywhere, but almost an entire MONTH'S worth of my notes is gone. The days aren't matching up anymore and I know I had the docs saved because I studied them not too long ago.