What's actually the 1st & last day?

We have been trying for 2 years to get pregnant and sometimes I think maybe it's cause I'm counting my days wrong. I count my first day when I see the first little amount of blood and my last day when I know it's gone evening if the bleeding is light and just when I wipe. Maybe I'm doing it wrong? Any help would be greatly taken in. Thanks in advance! 
​Also, any other tips and advice won't be turned down.