What Causes A Delayed Menstrual Period?

hi doctor ,,
me and my wouldbe hubby had mild sex recently,, i am a virgin, my hymen is not ruptured yet, but he leaked his sperms on my vaginal hole just before my period date,, but imediately i washed my vagina with water,, all this happened 1 month back,my last period was on september 7, till now i did not get my periods, what might be the reason? please tell and help me