Normal menstruation is between 3-7 days, less than 3 days is abnormal. If your period is one day and the volume is low, you may have menstrual disorders. You can go to the hospital for a sex hormone test to regulate the endocrine system. You should consider the possibility of pregnancy and use a pregnancy test. A positive result means pregnancy and you should go to the hospital for an ultrasound in time to prevent pre-eclampsia or ectopic pregnancy. Low menstrual flow can also be caused after curettage, abortion and intrauterine surgery. It may be caused by uterine adhesions and endometrial damage and requires a hysteroscopy. Menstruation can be affected by many aspects. If you are too tired lately, stay up late often, or have poor nutrition, it will affect the menstrual flow. You can take Ginseng and Spleen Pill and Agaricus and Yellow Essence Pill for regulation. Menstrual abnormalities can directly affect ovulation and cause difficulties in conception, so it is important to find out the cause and treat it in time.