Period stuff, blah.

My period was a day late, according to the app. 
My period also ended a day early, lasting 4 days instead of 5. That's normal, right? 
In addition:
TMI, sorry: Monday night into Tuesday morning my tampon was pretty dry; very little blood but there was still blood so I changed it. When it was time to change it again, it was pretty dry; very little blood so I did not use another after that, as I did not need to, meaning it was done. 
I went all day yesterday, including to bed and waking up this morning, no period. As I am trying to figure out why it stopped a day early; I put my finger up there just to see if it was truly done and it is just faint, a very faint sight of blood. It's nothing worth a tampon; panties still clean without a liner. It's ONLY when I wipe do I see the faint streak of blood. Again, normal, right?
What day am I counting as ending?