the last time I had my period was at 27th until the 31st of january and that time I was taking nordette pills, today is the 21st of february and im still not having my period. And the last time I had sex was 13th of feb now my left boob hurts af

Hello and welcome to EmpowHer,
If you are not having a period while taking birth control pills, you may need to switch to a pill with a different hormonal dosage, or use another method entirely. I highly suggest you speak with your gynecologist as soon as possible.
If you were taking the drug correctly, pregnancy is not possible.
Below I have pasted a link to a HER article explaining more facts about birth control pills:
https://www.empowher.com/providers/article/birth-control-facts
Faith