Maybe your testing too early?idk honestly,maybe wait another week or so and if it's still negative and you haven't started give your doc a call.good luck:)
are you heavy set? bigger women have problems with periods i know i did did you just recently get off medication like Birth control what happened to me i was on BC for 3 yrs and at one point they were giving me a different BC every MONTH for a year i finally said forget it and i got off birth control i had 1 period and then after that nothing and i had SO MUCH TROUBLE FOR 3 YRS TRYING TO GET STUFF STRAIGHT now i am pregnant could be your cycle changed and you dnt know it yet