I'l having my period, I think, for the last 4 days it has been black and very, very light. It has now stopped and never turned to red blood. I took a pregnancy test 4 days before this started because I usually have my period twice a month, but not this month and it was negative. It has now stopped, my husband and I don't use protection, I'm 35 and have also been surgically diagnosed with endometriosis.