so in June I had my first round of femara which lead to ovulation on day 18 of my cycle. I ended up conceiving but had a miscarriage at 5 weeks. I then ovulated on day 24 from when the bleeding picked up during miscarriage. I am now day 18 of my cycle with the use of femara and have not gotten a positive ovulation test yet. should I be worried or could I still get a positive?

I am so worried that the femara didn't work this time. Help please.