Not sure which to follow

Bee
Before I started with glow I use to track my menstrual with another app which also gives me a ovulation date the thing is that it is not the same date as glow so I'm not sure which to follow, this morning I used an opk and it seems like glows ovulation date might be correct but what if it was Monday like the other app said and now it's going down 😩😩😩 I'm so confused help!