pregnancy scare

hi I'm 16 and me and my boyfriend had sex on the 8th (2 days after my period.) and well I'm supposed have my period twice this month and I'm supposed to start tomorrow. anyways like 2 weeks about I started spotting. just once a and it was reddish pinkish (never spotted before that I know of$ and today I was cramping so now I'm freaking out if these are pregnancy signs.. please help