I started new birth control 2 months ago and I know it will knock your period off. I wasn't worried about it until today when I got sick and threw up this morning realizing I am 17 days late. I have taken two pregnancy tests and they have both come out negative. I have also noticed a random sharp pain under my right rib and I am not sure if it has anything to do with it. Do you think I am pregnant? What else could it be?

Well I don't mean to be blunt but were you with any guys lately

To put it bluntly. NO birth control is 100%. There is always a chance. Only abstinance is 100%. Retake the test if it has not started. Your hgb levels may not have allowed the test to register as of yet. But then again some women get false results with the urine tests and only the blood tests are the true predictor for them. Wish you luck espec since your so young.