Last day of period?

So I woke up this morning, removed my tampon, and there was just a small amount of dark red/brown (I'm guessing old blood). Now when I wipe, nothing is on the toilet paper. I know that once I get to work & start walking around, it'll come out when I wipe. Is this considered my last day of my period or was it yesterday? Or is it just a really light flow? I want to make sure I'm tracking my days right.