Please comment what you think :'(

so I had sex (pull out method) July22 & last August 6. then, when I woke up in morning (august7) i saw blood on my pajamas (because i want wearing any panties) then the blood never came back again. it was just like 2ml.. what could that blood be? and now I am having backpains.. I still have to wait 2 days before my period because my period will due on 11th or 2th! was it implanation bleed? my breasts are sore but I always have sore breasts when my period is coming though & its getting milder as I reach my period date. help me please or atleast calm me down :(