Hi, I Had Been Married On Nov Since Then My

Hi, I had been married on Nov since then my period cycle changed to 30 days to 35 days for pat three months ,this month it got delayed by a day ,on consulting a doctor the same day she confirmed negative with serum pregnancy test and suggested to take duphaston 10 mg.Will there be a chance of pregnant as its delayed by just one day.and will consuming duphaston abort if by chance I am pregnant .I am yet to start he dosage