Pregnancy at sixteen??

ok, so i am def. one of those premarital girls. i dont believe in doing it until your married. but my bf talked me into doing it so we did. and i regret it so much. like as soon as it was over i realized it was a mistake that i cant take back. we did it january 6th. and today is january 14. well we went about a minute unprotected then he went and put a condom on. well i cant remember when i had my period last i think it was december 12 or december 18th.. not sure though.. and i asked my friends if they thought i could be pregnant. and they asked if he med in me.. and i said idk. they said that i would know.. but im not sure.. but idk if i should start worrying or not.. but i have lost my appetite.. it might just be in my head though