Late period negative tests?

Alright ladies my period is now 2 weeks late! Over those 2 weeks I’ve taken 3 tests. One 2 days late, another 5 days, then the last at 8 days. ALL HAVE BEEN NEGATIVE?? I’m not showing any pregnancy symptom I experienced with my son but I mean 2 weeks late is a bit extreme. I’m not on birth control, I am sexually active but we always use condoms. Obviously those aren’t 100% effective though. What do you think? Should I keep testing? Should I contact my OB?