It is a normal physiological phenomenon, do not worry too much, it is best to take an early pregnancy test, if you are sure that you are pregnant, you need to pay attention to rest and strengthen the diet and nutrition. If you are sure that you are not pregnant, consider menstrual disorders, endocrine disorders, staying up late, mental stress, you can observe and see, early or delayed menstruation for a week is normal, endocrine disorders can cause breast swelling and pain, you can take the appropriate medication under the guidance of a doctor to improve the delayed menstruation. Breast swelling and pain may be associated with breast enlargement, breast nodules, breast fibroids and other related diseases, you can go to the hospital to perform breast ultrasound examination, under the guidance of the doctor to take reasonable medication, if necessary, surgical treatment.