my last date of periods was 17th of June 2012, till now I did not get my periods, I did a pregnancy check on 27th july 2012 Evening , & the test gave negative results , my doctor has given me duphaston to take for 5 days ..I am taking it from past 2 days 3 times a day, I really do not want a child , can I still be pregnant? what could be the reason for delay in my periods.