My period was 3 days late. It started on 11/23/12. It's heavy with some clots. My period is always on time. Last LMP 10/25/12. I had unprotected sex 6 days after last LMP & 2 times the following weeks. I've been having abdominal pain, & nausea. Is this a pregnancy sign? I don't believe it is implantation bleeding because of the clots. Miscarriage maybe? :'/.. any info is appreciated.