Help! When to test for O on Clomid?

Kristin
This is our first cycle TTC, and also my first cycle on Clomid because I don't ovulate. I am on CD11 today and my MD had me on Clomid days 5-9. According to the calculators out there I should start waiting to test until tomorrow (CD12). I'm paranoid I'm going to miss it but I also have heard that testing too early can give a false positive result. So should I start testing today or try and be patient and wait until tomorrow?