3 days late but negative test

Hi all
​I've  been having waves of fatigue, nausea, and indigestion... Which are part of my monthly pms for the most part. 
​I don't feel very different so I'm assuming we'll just try again next month.
 I don't understand why my period hasn't come yet when it feels like it's going to. 
​Anyone experience this? I'm always 28-29 days so this is out of character.
​Good luck to everyone!