If you have had protected sex, the chances of pregnancy are less. This is because the protection prevents the sperms from entering your vagina. But in many cases if the condom has torn or had leaked while removing, there may be a remote chance of pregnancy. The only way to ensure this is by doing a urine pregnancy test, done in a laboratory using an early morning sample of urine. if this test comes negative, you havent become pregnant. You can do this test on 14th October and see Just having a brownish discharge doesnt mean you are pregnant. The sex in the post ovulatory period may have dislodged the lining of the uterus which has mingled with your cervical secretions and given you a brownish discharge.