Thanks for your health query.
AM extremely sorry about your pregnancy
IN good hands, the chances of an IUI succeeding at best are between 15 - 20 %.
In your case, the chances are good, because you have already had one successful IUI earlier.
This clearly indicates that at that time atleast, your tubes were open.
The recent miscarriage
COULD have damaged the tubes.
Since you ovulated well, and follicles were good, wait and watch, and expect the best results.
If 3 more IUIs fail, you should undergo a laparoscopy
to ascertain fallopian tube
Meanwhile, do not stress
Take the medications as advised, and hope for the best.
Prayers for you!