Period 16 days late!

Alexandria
I haven't had sex in a while and I had my period last month and I don't know why mines late. Usually a week before my period my boobs swell up and get sore but that hasn't happened yet! Is that's normal because I'm concerned but I know I can't be pregnant because I haven't had sex in like 3
Months so I don't know why my period is that  late.