Had unprotected sex twice, one a weekend back and the other the weekend prior to. My period is hella late but I've also just started birth control and it's only been three weeks into it. Not sure if the meds have messed my cycle up and made it a later date or I'm pregnant? I've taken plan b after the second time and I took a birth control test the first coming out as negative. I'm a being paranoid or should I really worry? Only 17 can seriously not get pregnant right now, parents don't even know I'm sexually active help!