I don't understand! HELP

Im 19 years old..young yes I know but I'm married and have been with my husband for 5 years and we have a son who is about to be 3. I have been trying to conceive for 2 months and still haven't became pregnant. According to this app I was 3/4 days late. It is now saying I am fertile and ovulating (in the time frame of it anyways) I jus took an ovulation test and to ME which I have never messed with them, shows I am NOT ovulating. I'm starting to fear something is wrong