I'm scared, help!!!

Ok. So I started my period on June 3rd the same day my boyfriend and I had sex. Don't worry, it was after. Then we had sex again on the tenth and the eleventh. we used a condom all three times. I'm terrified though. I'm still in high school and I cannot get pregnant. I'm not old enough to buy birth control. I'm only 17. Can someone please give me some advice because I have no clue what to do. If I'm ovulating does that mean I'm pregnant or not. Or does it not matter? Please. I'm begging you for help.