Could i be pregnant? :)?

okay so my fiance and i had unprotected sex about three days into my period (gross i know but he wouldn't leave me alone and it was a very light period lol) and then again two nights in a row after my period ended, he did come inside of me both times. the day after the first night of sex (after my period) i had a teeny tiny bit of blood in my undies and later a very dark brown discharge, like left over blood sort of, the second day i started to have very light pink (bloody) discharge. is it possible for my body to already know i'm pregnant and be getting rid of all of the left over blood and what not from my period? which ended this past tuesday? could implantation bleeding happen this early? any and all answers welcome :) THANKS!