Has not had period in 5 months but not pregnant. last period was apr5-10 with reg periods. never sex. act. & no birth control ever taken. these past 3 days have had spots on pad, red & brown but darkish. what is the cause of this?

Secondary Amenorrhea: 23 year old lady with secondary amenorrhea of 5 months duration. The most common cause of amenorrhea or the absence of a period is pregnancy but several conditions such as polycystic ovarian syndrome, hyperthyroidism, some cancers, stress, obesity, anorexia nervosa, medicine, and other causes may cause this. Sounds like you may have some abnormal uterine bleeding see OB/GYN asap. Good luck.