IUI tomorrow at 11:30am

Merry Christmas, everyone! I’m scheduled to do IUI tomorrow at 11:30am. I had two follicles - 18 and 15 on day 10 monitoring ultrasound. Uterine lining was 6.5, so the doctor said to trigger on day 11 for IUI on day 13. I’ve only done IUI around day 15 or 16 where my uterine lining was much thicker. This is different. I took letrozole 7.5mg for 5 days and did the trigger last night. I’m nervous and scared that I already ovulated for some reason. I had egg white discharge around day 9.