Implantation bleeding

Katie
What exactly does implantation bleeding look like? What does "light" mean? I got off my period a week ago and yesterday I woke up to blood on my underwear but it wasn't even enough to go through and then there was nothing all day but again today there was a dime sized amount of pinkish blood. It was also mixed with discharge. Could this be implantation bleeding or would it be heavier than that?