Today is the 7th day ive missed my period and ive taken 3 urine strip tests that have come back negative,my period is always 28 days unfailing?

Possible reasons...: Pregnancy is the most common cause of a missed period. If not pregnant, other causes of a late or missed period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (such as birth control pills), hormonal disorders, etc… A home urine pregnant test is very accurate by 3 weeks after sex. Can retest after 1 more week.