Period or implantation ??

So AF was supposed to show her ugly face today, but instead she showed up 2 days early. I believe it was af and not implantation bleeding because I did have to use a pad/tampon and it was red. Usually have a 27-29 day cycle and it lasts 4 days. Today there is no bleeding or spotting.. has this ever happened to anyone else before??

Could it have been implantation bleeding?? Or in fact AF and just not last normal amount of time?? Any advice..?