What Causes Delayed Periods?

good morning

im an 18 yrold girl.. and im in a great dilemma today. last april 24 we've met with my boyfriend and something happened. that was actually my first time. im not sure really if it was totally a so called sex.. he inserted his part on me but that does not last for a minute. and we repeated it. but i think nothing gets into part any liquid coz he always wipe it and maintain it dry before the insertion.. im actually afraid. after that icident a week after i have my period and lasted for 12 days i think? then after that i waited again for my period and now its olredi june, im still waiting for my period coz it did not yet come. im afraid that i might get pregnant which i know my parents wud dislike and be disappointed to me.. im afraid really.. :( i love them. i really regret what i have done. i was totally carried away which i cant control coz i was tempted. but promise, it does not take long for a minute.. i am just curious why my period wasnt yet visiting me. am i pregnant? pls give a reponse to this Doc. thank you :(