What Is The Difference Between Implantation Bleeding And Menstruation?

What is the difference between implantation bleeding and your period? My boyfriend and I had sex on January 10th and 17th and I got my period on January 19th (at least that's what I think it is). My period does not have a heavy flow at all. It started off pink and has gotten to a bright red colour. What I am wondering is, is this implantation bleeding or my period?