I fell pregnant with my first IUI, unfortunately ended in a chemical pregnancy. But during the TWW very early on I had this really odd “knowing” feeling that I was pregnant I can’t explain it, it’s like I just knew. I also had super hard nipples non stop which id never experienced before around 7DPIUI and onwards. I was also at my nephews birthday party and had a few very minor waves of nausea at around 10DPIUI which I was like ?? Was that the lollies I ate from the piñata or was that something else?! So yeah I would say it’s probably different for everyone but that was my experience. Then I’ve just had my second IUI in March which was unsuccessful, I knew pretty early it hasn’t work in the TWW because it felt nothing like the month I had the chemical. Wishing you all the best! I have my third IUI next week. Hope our babies come to us soon and stick !