Can Follicles Develop Without Egg Inside?

Hi, I have just down my first round of IUI and am awaiting the result. On scans my follicle was 21 mm. Other cycles I have also had developed follicles on my right ovary. However, I have never detected my ovulation from ovulation test kits, even when I have tested twice daily and also when I was taking cholomophene. My question is, is it possible that I have developing follicles but no egg inside? Or am not ovulating? How would I find out? I pray the iui has worked this month and I am ovulating, just would like to know what the next step would be. Thank you!