usually I spot a little before every period and start either on the day or a day before I'm suppose to, yesterday I was 3 days away from AF and went I went to the bathroom there was quite a bit of blood, regular blood not light pink or brown. I put a tampon in and when I went to take it out there was nothing but a few drops of dark spotting on it. I didnt put a tampon in last night and I have no bleeding today.. could it have been implantation bleeding?