I'm late?

So I took a test on he 1st but it was negative, which I figured it would be. I was supposed to start my period today but I still haven't. I usually start on cycle day 26 and I'm never late. Well today is CD 27. I haven't had many cramps or body aches like I usually do before AF. I'VE just been really tired lately. I don't know if that is because I have family visiting or not though. When would be a good time to test? I almost feel like sense I tested negative a few days ago it's going to be another negative....