Need some advice

Hello everyone, need some advice! My last period cycle started oct 4-8 which is i logged it in sa flo app period tracker and ang sunod ko na period dapat base sa flo app is oct 26 (been using flo app for 5 years now and always naman siya accurate maybe ma late ng 2 days ganun lang) so lalabas po today e 1 week delayed na ako. Any thoughts about this po, thank you so much.