I don't know if I'm pregnant

I do not want to be pregnant I did not actually have Intercourse I am afraid his sperm might have gotten in me I do not know i am freaking out because march 20th it happened and I started my period that night and I am sure it was my period and now a month later I do not have my period, my periods are usually irregular but I am actually so freaked out I am only 16 and very religious help