I had a tubal ligation after my last c section 2 years ago. My periods have been regular since. I had an abnormal period in the beginning of may, lasting only a few days. I passed a large blood clot followed by spotting brown blood after. Since which I have had no period. My breasts are tender, I seem to always be tired, along with several other symptoms of pregnancy. I took a home pregnancy test and the results were negative. Even with a negative result, is it still possible I could be pregnant?