Yes, it's still possible that you are pregnant. Make an appointment with your doctor, and get your HCG level checked in a blood test...
Its possible but you may not have ovulated until late.if this hapens your period is later,give it few more days and test again.
i did not get a positive test with my second pregnancy til 7 days after AF was due. i tested negative all before the 7 days, so there is still hope:)