My husband and I have been trying for a baby since the 24-ish of May 2010 until now. My last menstrual period started on the 18 of May, 2010. We just had sex and now I am bleeding a bit and passed a raisin-sized (orange!?!) tissue. Is it more likely that we are miscarrying or that it is a sign of implantation bleeding? All of the ovulation calendars estimate yesterday as the implantation day.