Very confused !

Glow said i ovulated the 28.

<a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Period tracker</a> said i ovulated the 31.

First responce <a href="https://play.google.com/store/apps/details?id=com.glow.android">ovulation app</a> said i ovulated the 1st.

Very confused & i want to test. What do you ladies think? What are my chances of concieving?