Clomid and Uterine Lining?

Hello,
I'm about to start my 3rd month of 50 mg Clomid. My periods were always 5 days before Clomid. 1st month on Clomid was 3 days, 2nd month was only about 2. I'm afraid it's going to get lighter again this time around...

Could having such a light period be a sign that the Clomid has made the uterine lining too thin? I guess maybe there's no way to be sure besides an ultrasound?

I plan on this being my last IUI (it's my 4th) for now and I'm also scheduling to consult with another RE (it's over 2 hours away instead of 45 min, but I just haven't been happy with my current guy)...

Any insight would be apprecaited.