Implantation bleeding or AF

So AF isn’t due for another two days. But while at work last night I started spotting (never do this before AF) it started out as water discharge with slight pinks streaks. Later on it was more of the same so I thought the witch had showed. I put a tampon in cause once I start all hell breaks lose not long after. Well this all started at 1am and it still hasn’t picked up and it hasn’t been anything but a little bit of light pink with watery discharge on my tampons. I’m 13dpo today is it to late for implantation bleed??