Hi So I Was Wondering What The Difference Between Implantation

Hi so I was wondering what the difference between implantation bleeding and period bleeding is? And when does implantation occur? Because I had unprotected sex, and have been feeling really weird the last couple weeks and then today (my period was supposed to start two days ago) in the middle of the day I got a few very very light pink drops. And my periods usually are very heavy even in the beginning.