Hi Cally
If you are taking the progesterone daily and you are post-menopausal then you won't be having a follicular or a luteal phase because you wont be ovulating. It may well be that there is some residual cyclical activity - Im not exactly sure how this works but levels do apparently fluctuate for maybe several years post-menopause, though not dramatically - because the ovaries have more or less packed up. Some women appear to be more sensitive to this and can recognise these fluctuations - so I gather so maybe when you are feeling less good your oestrogen levels have dropped?
How long have you been monitoring this and noticing differences in the two weeks?
You definitely don't need more progesterone to alleviate PMS symptoms. Re oestrogen levels - if you are post-menopausal and you are achieving that level of estradiol - even though blood tests are not that accurate, that is a healthy level. However a few women - especially those who suffered severe depression during part of their menstrual cycle, need levels much higher than this to feel well. The late John Studd did a lot of work on this (we don't seem to hear about his clinic much these days - maybe now he has died, the clinic has also ceased?). Perhaps you are one of these and you need a much higher level.
I would suggest having another blood test and if it continues to be low, maybe switch to another mode of delivery because 4 pumps is theoretically quite a high dose - so perhaps you are not absorbing it well, and patches or Lenzetto spray may suit you better?
The only thing I would say is that 100 mg Utro may bit be sufficient to protect your womb if your oestrogen dose is higher....
Hurdity x