Scared!

Hey guys!So i'm 15 and i have a bf.So we have never had sex but he sometimes rubs my clit OVER my clothes.My period have to come today and if it don't come today i will be stressed and i will think what if i am pregnant.I have never had sex before but i am scared and i am always looking at my belly and it look bigger and i thought ,,i am pregnant".I know that it may sound stupid but i am very scared.