i think bcoz of the pills you are using, better to talk with your doctor.
You will get your best results out of a pregnancy test if you take it first thing in the morning. That is when your urine is the most potent and has the highest level of HCG in it. As the day goes on and you take in fluids from drink and food, your urine is diluted and the level of HCG maybe to low for a pregnancy test to detect. It is a possibility that your missed period has to do with the switching on and off your birth control. However, just to be sure, you may want to try taking a pregnancy test in the morning. Then, if it still comes out negative and you still don't get your period, call and have your dr check you out. When I got pregnant with my daughter, a blood test was really the only thing to pick up that I was pregnant.