I Had My Tubal Ligation Feb 24, 2009. My Period

I had my tubal ligation Feb 24, 2009. My period is always on time, normally a day or two early; this month I am 9 days late.. I took a pregnancy test and it sowed a negative result. I've been experiencing light cramping for the last 3-4 weeks, and my breast are so sore I can barely wash them with my loofa. I have a thickish, white discharge (light), could I be pregnant?!?