A week late, negative result.

Hi, I'm a week late for my period, and I've taken a pregnancy test and the result was negative. I've had unprotected sex a day or so after my last cycle ended and then again on the the day I was supposed to get my period. Any other times in between were protected. I'm freaked out because I don't really know what's going on lol. And I'm not really regular but I'm never this late. Opinions?