I was 4 days late for my period so i took a pregnancy test and it came back negative. Well this morning i woke up with some really bad cramping, and my period started. My concern is that i never have cramping as bad as i did today and my the first day of my period is always heavy. This period is different it started out medium not heavy like it usually does. What is the possibility of me being pregnant? Should I wait after my periods stops to take another pregnancy test or there is just no chance that i am pregnant?