Could I be farther along ???? H E L P.

So I found out I was pregnant the day after Mother's Day.. so the 15th, took one pregnancy test and got a dark positive. My period was due on the 16th, on which took two more test both super dark positives.ive been spotting for about three days (vvvvv light brown/pinkish barley noticeable), I did some research and it so happens that that might have been implantation bleeding, however , if the body starts producing HCG after implantation, how did I get positive tests before it. I also have to mention, last month on my period, I had a normal period only I spotted light light brown for like 5 more days (which never happens to me). Could it be that I conceived earlier than I though? If so I would be about 8 weeks.