I Had My Menses Last August 30, 2015 Up To

i had my menses last august 30, 2015 up to now my period didn't arrive,and i had unprotected sex 7 days after my first period and become ill 9 days after my first period due to tonsilitis and take cyproploxacin for a week, and now i took home pregnancy test uses my first urine in the morning 3x already and the result are all negative.