Implantation bleeding?

I was supposed to get my cycle on the first of August (I am very regular). I didn't get it so me and my partner had unprotected sex on the 3rd. After a week, I still hadn't gotten my period. On the 10th, I went to the restroom and when I wiped, there was discharge with a bit of blood. It went on for about 3 days, but I never wore anything other than a panty liner and even then I wouldn't stain the liner. Could that have been implantation bleeding?