Clomid

Ariel • ❤️Married❤️. Baby #1 & #2 due March 2017!
So I was on progesterone for 10 days and just got my period (2 days after it ended). My doctor said to start clomid on day 5 of my period. What if my period doesn't last 5 days, do I still take it on day 5? 
Looking for someone who has been through this!
Thanks!!