Hi, first of all stop worrying. Sometimes because of stress, hormonal imbalance or something like PCOS problem this can occur. As you said your period was on 28th October and 3 pregnancy tests are negative, just get ultrasonograpgy of pelvis done and Thyroid function tests, Complete blood count, Sr. FSH and LH levels. If everything seems fine then u can start Tab. DEVIRY 10 mg TWICE A DAY FOR 5 days. You will get menses in 7-10days after finishing tablets. You may need prescription from gynaec. All the best. And then you will require fourth generation OC pills for 6 months.

Sometimes lifestyle factors contribute to amenorrhea, for instance: Low body weight. Excessively low body weight — about 10 percent under normal weight — interrupts many hormonal functions in your body, potentially halting ovulation. Women who have an eating disorder, such as anorexia or bulimia, often stop having periods because of these abnormal hormonal changes. Excessive exercise. Women who participate in activities that require rigorous training, such as ballet, may find their menstrual cycles interrupted. Several factors combine to contribute to the loss of periods in athletes, including low body fat, stress and high energy expenditure. Stress. Mental stress can temporarily alter the functioning of your hypothalamus — an area of your brain that controls the hormones that regulate your menstrual cycle. Ovulation and menstruation may stop as a result. Regular menstrual periods usually resume after your stress decreases...thyroid profile should be done to rule out thyroid diseases...Consult nearest gynecologists they will do the needful.