Please read-Letrozole!!

For those who have used letrozole, what is considered the first day of your period?? I’m starting my first round and my doctor said the first day is first sign of any bleeding! Well after using the restroom earlier I noticed a little blood on the toilet paper, but seriously very little. Would you consider this the first day? I know this seems obvious but I really do not want to screw this up😔🤦‍♀️.