Blood In Mucus Before Period Mucus Spotting 7 Days After Start Of Period?

Mucus spotting 7 days after start of period? - blood in mucus before period

Hello .. I am 31 .... 29 began on Friday, a relatively normal (ceased bleeding spots spots) Wednesday to Friday, I saw a large patch of mucus, with a little black blood and a few hours of cramping .... I had sex (abstinence) during my time (Saturday and Sunday) ... It happened once, but has anyone any idea what could it be? This may be the blood of my time of ovulation, are left, I could be pregnant (that would be terrible for me ).... any input?