if you had IUI - even if your body delayed ovulation and implantation, you would have shown traces of hcg by the end of the tww - as i mentioned, i o'd approx five days after the IUI (if our scan dates are correct) - perhaps even longer - even if you go that late, you are almost guaranteed to have traces of hcg by the end of the tww. if you didn't and AF hasn't arrived, there are two options - either there was no egg to ovulate, so ovulation and the resultant hormonal variations didn't occur - or you o'd late - but i'm guessing there is no way you'd have gone this long without at least a HPT - if you're truly concerned, go get a test - if you conceived from that IUI you'll get a strong second line

from what has happened with me (i have no cycle at all without help) i'd say ovulation didn't happen and you're back at flat line levels... sucks to thing negatively like that, but having BTDT, it's the most likely outcome