What Causes Delayed Periods With Negative UPT While Having Pcod?

I am 29 year old height 5.3, weight 51kgs,I have PCOd since past 1.5 years...for about last 8 months i was on Obimet SR1000 mg ...now i have stopped taking that and my cycle is almost regular for the last 3 months...this month my period is overdue by 6 days...i took pregnency test at home but got it negative..what is the chances of me getting pregnent? should i continue Obimet SR1000 further