I had no symptoms after IUI. In fact, starting at 12 dpiui I felt exactly like AF was on her way. I was so convinced I was about to start, I didn't even look at the stick. Luckily MH did and said, "Hey, was this 2nd line already there?" Cue huge shock.
GL, and don't worry about your lack of symptoms. FX for you!
eta: you will never know if your symptoms are real until you get a bfp and look back on the last couple days. At 8 dpIUI, implantation probably hasn't even happened yet, so you wouldn't have any symptoms even if you were pregnant with quads.
We had an IUI on 11/25 - no symptoms except for being emotional during the 2 week wait, and the pregnancy test came back positive yesterday. Fingers crossed for you, too.