My period came late last month by 4 days which was odd. now this month, it is a week late and still not coming. i took at home preg test but negative.

Some thoughts...: In a woman with regular periods, some causes of a late period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (like birth control pills), hormonal imbalances, etc… Seeing a doctor is a good idea if symptoms are persistent, recurring, or worrisome. (pregnancy is a common cause of a missed period, if sexually active)