Hello, thanks for using health care magic If i did understand, you didn t see your period on the day you were expecting (i.e. may 16) and u did not see it even up to the 23rd of May. You did the right thin in trying to rule out pregnancy by doing a pregnancy test. Pregnancy test only gives a satisfactory negative value only when the test is carried out after the expected date of menses and repeated in a week s time to give another n negative value for conclusion. However, pregnancy is not the only cause of a delayed or absent menses. Other possible causes include; -Uterine synechia, -Infections -Stress and too much exercise. What you should do is retake the pregnancy test and meet a gynecologist for appropriate management. Hope this helps you Best regards Dr Achuo