Dark bleeding 4 days before period, could I be pregnancy?

Hi. I am due for my period on 4/6/07 however, when I went to use the bathroom today (4/2/07) there was dark blood on my panties. I didn't feel like I was going to get my period today. A week after my period my husband and I had unprocted sex and four days later we had sex again and I had ligh pink bleeding and cramping. Four days later we had sex again and I had light brown mucus, and now four days before my period I had dark red blood on my panty, does this mean I am pregnant. Also, Two weeks ago my breasts were a little sore and I had flu like symptoms, I had the chills but no aches and pains. Last week the chills stopped and the soreness of the breast was gone a little but the soreness is back and my breasts feel a little swallen. What can this be? Honestly, I am hoping to be pregnant and I hope Iam not psychologically beleiving I am pregnant. HELP!!