What counts as day one on Clomid??

Nikki • TTC baby #2 with PCOS
Hi ladies,
   I've got a message out to my doctor to clarify but as I scan the internet (dangerous!)- it gives me conflicting answers.  Is day one spotting or when there is more going on?  I spotted very lightly throughout the day yesterday but today woke up with an actual flow.   For those with Clomid experience-  When did you start counting day one? 
Thanks a lot ladies,  hoping for that rainbow baby this month!