Does this sound like implantation or AF

Kathryn
Hey all, so AF isn't due until Tuesday, but this morning I noticed slight brown spots, so I put in a tampon. 
After church there was almost nothing on it and still brown, when I wiped there was a brown tissue like thing, super tiny, but not normal for day one of af. 
yes I changed the tampon about two hours after my workout and there was maybe 1/4 of the tampon covered, but still dark, I saw some red so just assumed it was af.
My breasts are super sore, big symptom of af coming. 
My question is if this sounds more like  af or implantation. I've had three pregnancies, only one birth and never experienced implantation.
Sorry this is so long. Thanks for your help!

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