I was supposed to get my period about a month and a half ago, and haven't.  I went off birth control about 6 months ago, and my period has been a little weird or off ever since.  My boyfriend and I are always very careful, and my body feels abslutely no different.  I took a pregnancy test about 2 weeks ago and it was negative.  I have gained some weight in the past month, but I blame that more on junk food binges and irregular exercise patterns. I'm about 97% sure I'm not pregnant, but I'm just wondering if there's a chance or if something else could be wrong.