So I started my period today.....FINALLY!!!

I knew it was going to start, I just needed it to hurry up so I could start my Clomid. Here is my question. My sister and a few of my friends are all going through the same thing and they have heard different things from their different doctors. From my understanding, day one of your cycle is the first day your period is red and flowing. My sister and some of my friends say it is when you first start spotting. I need to know when the first official day of my cycle is so I can start taking my Clomid on day 5 of my cycle. Can anyone help me with this confusion without having to call my very busy GYN?
Amber