CP after first IUI

Hi ladies-I found out I was pregnant after our first <a href="https://glowing.com/glow-fertility-program">IUI</a> on 11/15. For some reason I had a feeling things weren’t right(no physical signs, just a gut feeling/worry) two days later and I was right. My levels went from 61 to 14 in from Thursday to Monday. I’m waiting to get my period from this chemical pregnancy. I was on progesterone but have stopped. When can I expect to get my period? I’m supposed to take Letrozole in this next cycle and am not sure how the drugs and CP will impact my ovulation day. Any insight would be helpful!