Ladies HELP !!! 10 Days Late !!! Fertility Window Tomorrw

Nikki

So Ive Never Missed A Period Except When I Was On BC About 3-4 Yrs Ago , Ive Taken Several Pregancy Test Last One Was Thursday Or Friday I Didnt Want To Take Anymore Because I Get SAD Everytime Its Negative , But Anyway My App Says My Fertility Window Starts Tomorrw Do I Just Continue To Follow App Like Normal Or Is Everything Off And Mixed Up Due To Missed Period ????