Spotting at the end of a period...

Catherine • 33- have a beautiful 6 yo DD and so excited that she is going to be a big sister in December 2016!
Do any of you consider that still *on* your period? I had a 6 day period with legitimate flow, which tapered off last night. Today, I have very very light spotting (mostly just wiping.) Husband and I had sex last night, so the post coital leakage (am I the only one who had this last like, a full day after??) is blending with the spotting, but from experience, if I was on my period, this would be a lot heavier. 
Since I had a 24 day cycle last month, Glow is saying my fertile window starts immediately- so should I tell Glow I'm still on my period, or should I consider this just spotting and track as if this the beginning of my fertile window? (I can't believe I'm 32 and asking this question.)
Thanks in advance!