Suggest Methods To Prevent Pregnancy

Hi, may I answer your health queries right now ? Please type your query here...Hi I started sprintec birth control on thursday to prevent my period from coming because i was going to see my boyfriend on sunday. I had unprotected sex on sunday night. I have been taking the bc since then and now i realized i started my birthcontrol on the 1st week thursday not the sunday. My question is im scared that I could get pregnant what are my chances?