When to test...

Hey ladies,

Just looking for some advice on when I should test. AF is due tomorrow according to glow, but I don't have any spotting like I normally would before she comes. My periods fall anywhere between the 25 to 28th day (tomorrow is the 26th) my boobs are pretty sore and aren't going away like usual before AF. I don't want to test too early in case implantation hasn't happened. If AF doesn't show tomorrow should I test in the morning or wait? When should I test?