What Is Causing My Lower Abdominal And Thigh Pain After Unprotected Sex For The First Time And Took Postinor-2 After 21 Hours During Mid-cycle?

Hi I had unprotected sex yesterday and it was my first time. I took postinor 2 after 21 hrs, I am in my mid cycle . I am also having lower abdominal pain, thighs pains too after the intercourse, what could be the reason. Is there chances that I could get pregnant