I am twenty days late on my menstrual cycle. i took a hpt test but it was negative about a week ago. i had some light pink spotting n nothing else. ??

Menstrual period: Reasons for missed / late period include: an anovulatory cycle in which no egg is released, marked v or ^ in weight; eating disorder; Over-exercising (endurance athletics), stress, travel, significant illnesses, oral contraceptives & other meds, Illegal drug use, breast feeding, hormone imbalances and medical problems (i.e., PCOS). Pregnancy is #1 reason.