two different ovulation dates??

<a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> says I ovulate tomorrow but Glow says I ovulated February 10th. Which one should I trust more? On the 10th of this month I started spotting pink and brown, and again yesterday and today. And also <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> says I shouldn't have a period for February but Glow States it should be the last week of February. I had sex around January 31st and a period January 24-29th. So which app would be more correct?