When was nmy last day? confused

Hi everybody. As probably everyone knows now from my previous threads, i've come off the pill and this is my first proper period since coming off it. Before the pill i never really did my cycle days so now i havent got a clue in how i'm meant to be counting my days. I want to see how long my af was on for as before i was on for almost 2 weeks and so i dont know when to count my last day.This might be tmi by the way. I'm on cd8 and yesterday (cd7) for about half the day i had that browny red stuff thats like gooey you know what you get last before nothing so would i count yesterday as my last day of af or the day before where i had proper bleeding?
Thanks in advance ladies x