So boyfriend and I had sex about 3 weeks ago using pull out method and I currently use no birth control but I have no signs of pregnancy.. but no signs of me getting my period so what does that mean?? (I usually have bad cramps right before I get my period and during my period and barley ever late)

UPDATE*** 10/31/17

I got my period!! With vengeance but I got it and I’m pretty happy about that! I’m not sure if I’m ready for a baby yet.. thank you for all your support