Nervous

My husband and I are on our third cycle ttc. I know that isn't very long at all. The first month I got about 5 days of positive pregnancy tests and then started bleeding. I'm guessing it was a chemical pregnancy. Doctor said everything looks fine, i have follicles, she didnt see a reason we should have a hard time getting pregnant. Last month I monitored my cycle with the clear blue digital ovulation predictor. It never showed ANY signs of ovulation, always a blank circle. But i did have a period. This month I've been using first response regular "read the double line" ovulation predictors and my fertile cycle is supposed to start tomorrow according to this app but the lines are not getting any darker. I'm starting to worry about whether I ovulate. How many months before I should mention this to my doctor?