Period or implantation ?

Period is usually 6-7 days long . Period was expected the day it came. It was light the first day . And the 2nd, and 3rd it was heavy , filling up super plus tampons and blood clots . And today the 4th day it was light when I first changed it and now there’s nothing ....is it just my getting lighter since it’s almost done . And I have these period cramps I always get, been sleeping a lot .. am I just overreacting ?