Welcome to HCM This is Dr Amit. Missing a period but having a negative pregnancy test is one of the most common complaints women seek advice about. The medical term used to describe absence of periods is amenorrhoea. There are two types of amenorrhoea: primary amenorrhoea and secondary amenorrhoea. Secondary amenorrhoea is when a woman who has had normal menstrual cycles stops getting her monthly period for six months or more Common causes of secondary amenorrhoea (when a woman who has had normal periods stops getting them) include: Pregnancy ( which is excluded in your case) Breastfeeding Stopping the use of contraception Stress Poor nutrition Depression etc I will advice you to seek medical advice from the gynecologist as early as possible. He/she will do pelvic exam along with ultarsound to identify underlying etiology and they will start the treatment accodingly Regards