What Are The Chances Of Conceiving Having Unprotected Sex On 25th Day Of Menstruation?

hi I am 28 years old and living with my husband. I had unprotected sex with my husband and had emergency pill, Then my period takes before 7 days than usual time. I heard that it is safe without protection on 7-8 days from period. So we did.According to my last period, my period should take on 7th ocotber but till date(18th oct) no menstruation. I had pregnancy test at home and found negative. But I am scarred whether I am pregnant as we don't have plan for it.