Implantation bleeding?

Earlier this afternoon I noticed the toilet paper was tinged with blood, this has continued thru out the evening and now into the night. I am having mild cramps in my pelvis and lower back. AF is due Friday (the 20th). I know implantation bleeding happens 6-12 days (usually) as of today I am 11 days pass my first positive ovulation tests.... Took pregnant test and it came back negative?