Does implantation bleeding always mean your pregnant?

I'm not sure cause I heard people say you can have a period while pregnant which is getting me scared. I did have Implantation bleeding 2 weeks after that I got my period which was strange it wasn't painful at all. I'm having periods every month but ever since I had Implantation bleeding they have gone in a pattern. I'm only 16 and under 5ft as well.

From XxPink PrincessxX