Period or ?

So I'm 13 dpo today and period is supposed to start tomorrow. Yesterday I started getting very light brown spotting only when I wiped. I dont have any symptoms except maybe slightly sensitive nips and maybe my boobs feel a tad heavier than normal. This morning I went to pee and wiped and there was a medium amt of brick red blood on the toilet paper when I wiped so I got discouraged and put in a tampon. This afternoon I went to take the tampon out and only 1 side of the tampon was brown and had a glob of brown tissue on it. Not a blood clot. It was clearly tissue. But now theres maybe a dime sized amt of brown but only when I wipe. Is this my period coming or could there still be a chance that was implantation? Test this morning was BFN. Tia!