I usually start my period on the 12 of every month and they last about 4-5 days. One month I spotted for 2 days on the 12 but the next I started on the 1 for 3 days with heavy bleeding but sometimes when I whipped it was like dried blood 'clots'. I have also noticed my breast have gotten heavier and sore and some foods really upset my stomach and I've always ate everything. I've took a test and it came back negative. Could I be pregnant?