hi,i m 21 yrs old a girl.I had sex with my boyfriend on 9th July at night and 10th July at morning,i took i-pill on 10th July at 12 p.m.I missed my period date, it was 11th July,as i took pill,so it should be delay...But i check my pregnancy test on 18th July,it results negative,and my periods also not come...so am i pregnant?