Period twice in a month

Usually my period is very regular, I had my period November 4-9 (on schedule) and then got my period again yesterday (November 19). At first it was light so I thought maybe just spotting, but today it’s full on bleeding. I’m not sure why I’ve gotten it twice in a month, that’s not usually regular for me (the only other time this happened was when I first started getting my period). Any ideas on what it could be?

(Me and my bf have unprotected sex regularly (not sure if that matters but just putting it out there just in case it’s related))