My period came three days early and lasted for three days could i be pregnant ?

Doubtful,...: If you indeed had a period,that simply came 3 days early, it is doubtful you are pregnant, as it is not "uncommon" for periods to be a few days early or late. If you had unprotected sex mid cycle when you ovulate, then you are at increased risk of getting pregnant. You can always do a preg test. If you do not want to get pregnant-see the Dr. for Birth control & use condoms also to prevent STI's