IUI on what cycle day?

So I’ve had 2 IUIs both while take clomid. Both were on cycle day 14 because day 12 landed on a weekend. The second one was successful but unfortunately I miscarried. My doctor said to set up my next one as cycle day 14 since I’m taking clomid again and it obviously worked. When I called the make the appointment the nurse totally made me second guess myself about cycle 14 and not cycle 12. She even checked with the doctor (who said it was okay) and said that everyone’s body is different.

Now I’m freaking. What if I go and I already ovulated?? What cycle day did you do your IUIs on? Should I just relax because it worked last time on day 14?