Lack of menstruation is the first (but unreliable) sign of pregnancy. I recommend you take a home pregnancy test. If the test is positive, then it is possible that you are pregnant. You can schedule a visit with your gynecologist for a vaginal ultrasound to confirm if the pregnancy is normal or not. If the test is negative, then you are most likely not pregnant but may be experiencing menstrual cycle irregularity. For diagnosis and treatment, you can visit your gynecologist to help identify possible causes of an irregular period.