This Month Has Come And Gone And I Have Not

This month has come and gone and I have not received a menstrual cycle since Dec... I have taken a preg test each month and al of them have been negative. I have been very bloated and my breast very sore just recently.. I have felt some weird feeling in my stomach and I woke up this morn with some really bad stomach cramps. My Dr app isn't untill the 14th should I be worried?