spotting and then it stopped and started...

I started my period on a thursday & then I stopped friday night early saturday morning around 1 am. it is sunday and I started spotting and then it stopped and started back like 1 hour later, it has never happened to me before. I never spotted in my life. and my normal menstrual cycle is 3 days.could I be pregnant. my cousin has the same problem and she was pregnant, my best friend had her period for two months and then found out she was 2 months pregnant. I have sex alot and no protection but he pulls out.... I am just wondering cause i've never had this problem before.