Thank you for your query.
The possibility of fertility
/ conception depends on many factors.
Firstly your ovulation has to be confirmed, since your IUI was done, i assume you ovulated properly.
your husband's semen analysis
has to be normal.
Your fallopian tubes have to be open, and the patency tested by HSG / preferably laparoscopy
400 is prescribed for luteal phase support after IUI in case you conceive.
IUI definitely raises the chances of pregnancy
, and has a success rate of 10 - 20 %, but its success can be lowered by your age, presence of fibroids etc.
yes, after IUI and using Susten, you do have chances of conception provided all the other factors are normal.
And do not panic till you have / miss your next period.