Hi!
Firstly, talk to your doctor about Femara and/or Metformin. I like Femara much better than Clomid. It doesn't sound to me like the Clomid is going to work for you.
The monitors are not affected by the medications, if there is no sign of ovulation, it is probably because you aren't ovulating. Two other ways to check for ovulation (I recommend them both at this point!) Ultrasound to look for follicles--if you were my patient, I would start ultrasounding about cycle day 11 or so. And a progesterone level on cycle day 21.
Now about the Premarin--Clomid helps to induce ovulation ( if it works) but it can have some side effects on the cervical mucus and the uterine lining--both can be thin and unfriendly. (Femara is much less likely to cause these problems). The premarin can reverse the side effects of the clomid and cause your lining to thicken and your mucous to increase ( the mucus has to support the passage of the sperm, and the uterine lining has to support the developing embryo ).
I don't know why you are resistant to the Clomid--is age a factor? If so, you may want to test your ovarian reserve. Do you have PCOS? if so, the metformin may really help.
I hope this is useful!
Dr B
Now to answer your question.