Help plz 🥺🥺

I got my period like 3 days late last month and it lasted 4 days which it normally wouldn’t. Anyway now it’s getting the time where I should be getting it because im having cramps and back pain but still I’m around 3 days late agian. I haven’t had sex in like 2 months and we used protection so Ik I’m not pregnant it’s just scary to happen. Is it normal for cycles to change ???? I’ve been having cramps for like 2 days and still no period