help I have questions.

So I have been cheking to see if I am ovulating and all say no. Please explain when I am fertile i am to have sex right? But then i get a msg today from glow that I am 1 day away from ovulating. 
I had a baby girl 10-03-16 but I was only 19 weeks, baby did not make it. She came out of her sack. 😨and now would like to try again. But I am very confused.