well, I am on cd6 (have 1 more pill left of clomid before I start the estradiol).
Have experienced nausea after taking the pill in the mornings, a little dizziness/drunk feeling, slightly cranky, and some constipation. All in all, it hasn't been a bad experience so far. It also cut my period shorter than usual and ALSO increased my libido for some reason.
I am going to keep track of my symptoms, etc here on this thread, as there is woefully little info on women who take clomid in their 40s on the forums. Lots of IVF, but very few clomid with the combo of drugs I am taking posts.