scared.. any advice?

my boyfriend and i were sexually active on the 11th and 14th, my period was supposed to start either on the 14th or 15th and it still hasn’t come, he did not cum in me or anywhere near me the first time but on the 14th he came on my stomach but we quickly made sure nothing got down there.. any ideas or anything to calm my mind considering my period has been on time the last little while