What Causes Delayed Periods In Spite Of Safe Sex?

hello Dr. I have a problem, i am supposed to have my period on the 5th but yet i have no symptoms nor any belly pain yet which normally i have prior to my period. am afraid that i may be pregnant, i have not taken any test yet. But during our sexual intercourse, my husband didn't ejaculate inside at any point in time. Do you think i am pregnant or just a delay in my periods?