late period

stopped bc pills abt five months ago. last time i had sex was with my ex with a condom at the end of october. when i was on my bc i didn’t have a period, but since stopping it i’ve had a period during the months of October, November, December, January, and February. I am currently two days late on my period according to my app. I haven’t had sex since tht time with my ex in October and I’ve had my period since. I’m just not sure why i’m late considering i shouldn’t be pregnant.