Ovulation with Chlomid?

Hi! I’ve been taking Chlomid for a couple months now and have yet been able to pin point ovulation. If you’ve taken Chlomid before, do you remember what cycle day you ovulated on? I went for my follicle study today and my doctor said he thinks I ovulated yesterday or the day before. How would he know that it already happened? He said I still have a couple enlarged follicles (10mm-16mm) on my right and a few on my left still too (10mm-12mm). Thanks!