Implantation question!!

Jocelyn💋 • Have a wonderful life that I have to thank the Lord for❤️ have a son and expecting baby girl🌹
So I got my BFP yesterday and the day before. I tested 2 days in a row. Today when I went to the bathroom I whipped and there was light pinkish blood on the toilet paper. 
When do people usually (if you did) experience implantation bleeding? Can it be after a BFP, around the time AF shows, or what? Please someone answer this. 
Has a MMC 2 months ago and been trying every since.