hi gisselle 🙂
the same thing happened to me for 2 months in a row after i started having sex with my fiance. basically my period would end up being about 4 days late every month. and then i would test before getting my period and it’d always turn out negative [and like the next day i’d get my period]. i would really just start to get concerned when you’re almost 2 weeks late. this is the time when most pregnancy tests can detect hormones with a good amount of accuracy.
if your period comes it’s usually as a result of your egg not getting fertilized. the uterus no longer needs the lining that is built up throughout the month and so it ends up expelling that along with blood. so if no fertilization occurs…. and no implantation occurs… then you’re not pregnant.
however if you still feel uncertain about whether you’re pregnant or not my suggestion would be to visit a doctor and get tested there. 🙂
good luck… and let me know how you are. 😛