Help!!

Today is the last day of my fertil week. But since yesterday ive noticed brown discharge everytime i go to the bathroom. Today it kept coming. Sometimes its a lot.. Sometimes a few drops.. and it has a little bit red in it.. But its not the same as my period. (It also smells bad) Can this be implantation bleeding? I had sex with my partner 3x times (everytime a other day) but on the day we had the highest chance he didnt finish during sex because i started having pain. So we stopped..