11days late and negative pregnacy test could i still be pregnant? if not what is wrong with me?

Menstrual cramps: It depends on how irregular your periods are but it's unusual for a woman to never have an irregular period. The worry signs would be high fever (101+), a positive pregnancy test, a family history of cervical cancer, excessive bleeding (especially if you feel weak or dizzy), or unusually severe cramping. Stress is the most common cause of missed or extra periods.