Hey all, I was hoping to see if someone could help me calculate when my period should show up. I typically have a 29 day cycle, my period started on dec 23 and lasted for about 6 days. positive LH test Jan 1st. So far all preg tests have been negative. Glow is predicting my period to come on the 16th. However my other app (natural cycles) and countdown to pregnancy.com is saying I should expect it around the 20th. Which source should I go off by? (Currently on cycle day 20 today)