Advice PLEASE!!??

I am currently on my first cycle for IUI. Today I had my third ultrasound and blood work, and have been taking Follistim. I am also on Cd9. When the Drs office called about my results today, they told me to decrease my Follistim , and come on again tomorrow but ONLY for labs this time. Is this a good thing, bad thing? Why only lab and no Ultrasound? I've always had the two together. Getting nervous that something is wrong. Any ideas : advice?? Any would really be appreciated!!