I need help deciphering this chart!

​​this is my 2nd cycle since chemical pregnancy and I didn't want to use opk I wanted to just trust God. However I don't know when I am going to ovulate. I have never tempted before and it's hard to always do it the same time bc I work 3  12 hr nights as a RN. I am going crazy over here and don't know when to stop doing the deed!