Per several different apps and tracking my period I'm now 4 days late and I usually have a 5 day period with a 28 day cycle inbetween. My LMP was 08/11-08/15 and both apps said it would be due on Sept 8th and end the 12th. I'm also extremely active and workout twice a day 6 days a week so I'm unsure of what it is... I haven't missed a period at all and I've been this active now for almost a year. And have not been late once. I took a pregnancy test and it said negative. Can anyone relate?