Hi Diamondqueen
Sorry to hear about your tiredness and other menopausal symptoms.
The one good thing is that tiredness and brain fog are NOT caused by oestrogen - quite the opposite. The sedative hormone as sheila99 says is progesterone. Brain fog can be caused by progesterone and also by low oestrogen ie due to menopause. Oestrogen dominance as a cause of such symptoms is a myth - though excess oestrogen in peri-menopause can cause bleeding problems so the two need to be balanced to protect the womb. If you haven't had bleeding problems then you would not benefit from taking progesterone along, which is sometimes prescribed in early peri-menopause when ovulation is skipped in some cycles which can result in heavy bleeding.
PCOS is a condition which I imagine requires specialised treatment. For example one of the features of PCOS is raised androgens, and deficiency in these post-menopause can result in lack of energy and brain fog, hence some women take replacement testosterone, so if you are peri-menopausal maybe somethng has happened to your testosterone levels?
Can you ask to be referred to a specialist - in menopause and who knows somethong about PCOS and can do other tests. eg did you have T and SHBG tested as well?
I don't know how sudden increase in oestrogen would affect your condition such as to increase tiredness but I would agree with sheila about getting thyroid etc tested too, thouygh as you suggest this might have already been done when you had the extensive blood tests done last year?
Hurdity x