Pregnancy related stuff. Of pregnancy?

I am 28 years married women. My periods due date was August 10th, but I didn't get periods this month. I had delay of 10 days last month too. My periods were regular earlier usually deal at of 2-7 days(that's common for some people I guess). When I visited doctor last time for annual health check up.they said I have PCOD, temporary thyroid etc..Also, in general my bleeding is very low during periods. I did pregnancy test 4 times at hone even With early morning urine. It was negative all the time. Should I consult doctor now or wait some more time. Is the delay might be due to PCOD problem?I don't have any symptoms of pregnancy like vomiting, tiredness etc though.after how many days of missing period,we get accurate results of pregnancy?PLEASE suggest.