My Menstrual Bleeding Was Supposed To Have On 28/12/2015.i Had

my menstrual bleeding was supposed to have on 28/12/2015.i had unprotected sex last month several times.i did not have my menstrual bleeding yet.pregnancy test with urine hcg strip came positive on 13/01/2016.i want an abortin with pills.please advice me on the pills i should take.thank you.