Period due today

Danielle • I'm 28 years old with 2 boys! A 4 year old who will be 5 in October and a little boy that turned 1 august 9! My husband and I found out september 14 that we are expecting our 3rd baby! Praying for a happy healthy pregnancy to everyone!!
I'm on this app and ovia according to this app Im supposed to start today according to the ovia app I'm supposed to start the 28 I took a test today and BFN! I'm not sure what app to follow because I'm not having any period feelings at all!