Lynn,
I will try and answer some of your questions referring to my own experience. I started my sympthoms around 39ish. From talking with my Mother, so did she, and my grandmother as well. I had hot flashes right off the bat, dizzy spells, weakness, and a type of mental confusion. I am sure that part of it is like someone with dementia. But anyway, those sympthoms were partly (according to the doc) from the onset of menopause, and partly from the lack of estrogen. An increase in my estrogen dosage helped quiet a bit. Oh yeah, and I looked for fresh meat sometimes too. Raw.
I'm 52 and still occasionally have hot flashes...especially if my blood or estrogen is low. I am not a nurse, don't know what that means or why (don't want to know) but all I can tell you is how I feel BEFORE and AFTER my estrogen is increased. I can almost tell you when my blood is low by how I feel, or estrogen for that matter. The flashes start. I think each person is different. But it has been 12 years for me and I am still going thru it. By the way, I don't know if this has anything to do with it or not, but I start going thru it immediately after having all my parts taken out.