Thanks for the query.
If you had unprotected intercourse
around the time of ovulation, there is possibility for pregnancy
You better go for ultrasound
By that the possibility of pregnancy can be identified.
If there are no signs of pregnancy, ultrasound can detect the cause for your delayed periods.
And after that you can go for tablets to induce withdrawal bleeding.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429