Bleeding for 3 weeks w/foul odor what's wrong?

I had a tubaligation 4 years ago. Last year I experienced 2 weeks of vaginal bleeding bright red in color. Doctor did pregnancy test and it came back positive. But no pregnancy resulted. I also started lactating. I just had a period starting March 12th, 2007 and it was dark brown almost dry looking. Then the following week I began bleeding bright red. Now I am spotting when I wipe and there is a foul odor and I've noticed body tissue in the toilet. What could this all mean? My tubaligation procedure was a cut and clamp. Where they removed the connecting sections of tubing and then clamped the ends.

Could it be undoing itself somehow? Could it be confusing my body? Am I getting pregnant and then constantly miscarrying? Is it a sign of an infection? I really need some answers, it's affecting my sex life and overall moral.