I have a very regular cycle. My period was about 3 days late, and started with very very light brown spotting. The next morning there was little blood, but it escalated to what seemed like a light flow for two days, then went back to brown spotting. Ive had cramps,tender breasts, mood swings, every odor gets to me, and I have a sudden HUGE appetite. My boyfriend and I had unprotected sex near the time of ovulation 2 weeks ago, but he did not ejaculate inside me. I took a pregnancy test and it came up negative. What could this be?