Strange bleeding

Hello, my period is very regular and has been since I was ten! My last period stared on the 30th of November! eve says it’s my fertile week (almost the end) and today when I went to the bathroom I noticed I was spotting! Doesnt look the same as period blood! More pink with hints of brown! I also have a light cramp! I’ve never spotted in between a period. Has this happened to anyone else? I’ve also had a lot of sex recently with my boyfriend idk if that changes things