When should I test again?

Hi everyone! I've been lurking around Glow for quite some time and I love all the posts and encouragement!

But I have a question...

This is the first time I haven't started my period on the day I was supposed to. I have very regular periods and now I'm 2 days late according to the Glow calendar, I took a test yesterday that was negative, I'm having light cramping but no bleeding. How soon should I test again?

Here's my first test. No faint line..nothing. possible my cycle is just changing?