What Could Be The Reason For Not Getting My Period For Close To A Month After Taking Meprate?

Hi, I don t have periods from last 3 months and I got married 1 month before,my preganews test was negative and also had hormonal test all normal but found pcod problem, as per doctor s consultation I took meprate tablet twice a day for three days ...it s already 20 plus days has gone but no periods are still there what is reason