Hiya, just a quick question. My cycle is 26 days exact and I've been using glow since June 2015 and it hasn't changed but this month it's saying I'm not due my period until 17th, but my last period was 15th December so I should be due today, 10th January. Does anyone know why glow has suddenly changed its prediction when I've have a regular 26 day cycle? It's making not want to do a test incase I'm testing too early. Thank u