It is possible to have no period (amenorrhea) and not being pregnant. Amenorrhea is the first sign of pregnancy, but not every case of amenorrhea points to pregnancy. If the blood pregnancy test was negative, then you are definitely not pregnant. Another reason you might be experiencing amenorrhea could be the presence of some kind of functional ovarian cyst. Functional ovarian cysts are hormonally active and they are typical for women of your reproductive age (29). Cysts can either originate as follicular or luteal cysts. Hormones (estrogen or progesteron) produced by a cyst can prevent a menstrual period. Such cysts usually exist between 2-3 months and end in a heavier period. To confirm an ovarian cyst, you must perform an ultrasound scan at your gynecologist's office.