Some people get that mid-cycle spotting around o time--it's most likely that. Seeing a spot of blood during ovulation is considered an excellent fertility sign. It could be good sign that ovulation is approaching. Basically it states that the spotting is because the egg is bursting from the follicle and can cause red or light pink to brown spotting right before or during ovulation. Unless it is associated with painful cramping, I wouldnt worry. Take it as very good fertility sign. Dont bother much about negative opk; it could be possible that you are missing surge. Blood tinged EWCM, however is considered as a good sign of your fertile period is starting. Are you charting temp throughout cycle?