Am I actually late?

Emily • TTC baby #1 since July 2017 💕

All 4 of my fertility apps say that I’m 3 days late. But every month I get my period the day after cycle day 28 (so what would be cycle day 29) yesterday was cycle day 28. Usually my apps are good at guessing the day my period is due so I’m confused. Am I actually late or am I due today and actually late tomorrow?