What Causes A Missed Period In Case Of PCOD?

i got married on may 2010.For may and june i missed my period.So i expected that I'm pregnant. But when i met the doctor my pregnancy test result was negative.I was terribly upset to know that I'm having pcod.After taking the tablet prescribed for me i got my periods on july 7th.After that we had sex and now i'm missing my periods.I want to know whether it wouild be a symptom of pregnancy or it is due to PCOD?Is it possible for me to get pregnant as soon as possible?