If you are not pregnant, you may have the following reasons: 1. The early stages of pregnancy will show a history of menopause, along with the symptoms of stomach distension. So you can use early pregnancy test paper or go to the hospital to take blood to check the human chorionic gonadotropin to check if you are pregnant. 2. If you are not pregnant, you can do an ultrasound to see how thick the endometrium is and to project approximately when you will have your period. Generally, if your period is delayed within 7 days, it is within the normal range. If you are still not getting your period for more than 7 days, you can take oral medication to promote the onset of menstruation. 3. You can check the level of female hormone 6 to see if there is endocrine disorder and treat it with the right medication according to the test results.