Is it Implantation bleeding??

Jess • Mon, Dec 30

I'm 12dpo,should be getting AF in 2 days and have had absolutely no PMS symptoms (which I always do!) Woke up this morning and noticed a brown discharge when I wiped. it then barely filled up a panty liner and then stopped mid afternoon. it's now night and I only get a tiny bit when I wiped. Not sure if it's my period starting early, or implantation bleeding. Any thoughts?