Hi, Thanks for the query. If you had unprotected intercourse around the time of ovulation, there is possibility of pregnancy. But just by symptoms we cannot come to one conclusion. Usually urine pregnancy test can detect the pregnancy, after one of missed period. Menstrual cycles can get altered depending on many factors like : - Hormonal imbalance due to poly cystic ovary disease, stress and strain, weight changes etc. - Thyroid hormonal abnormalities. - General conditions like anemia etc. So, once go for blood test for pregnancy. If the test comes negative, the possibility of pregnancy is less. Then consult gynecologist once and get evaluated to find out the exact cause for missed periods. Then with her advice you can go for tablets to induce withdrawal bleeding. Take care.