I'm sorry for your cancer diagnosis. Since your ovaries were removed, you're in surgical menopause. The ovaries of women who have all their parts continue to produce hormones (small amounts of estrogen and a good amount of testosterone) into their 80's. Typically, these women have the worst menopausal symptoms during perimenopause when ovarian hormone production is erratic. Things tend to settle down shortly after menopause. But without ovaries, the symptoms can be severe and last much longer.

I'm not sure why this is but sometimes an HRT that had been effective stops working and we have to switch to something else. Oral estrogen requires a first pass through the liver and your liver may not be as efficient as it used to be hence the worsening symptoms. I also use estradiol tablets (Estrace generic which is equivalent to Elleste Solo) but instead of swallowing them, I let them dissolve between cheek and gum which bypasses the liver. You could try this method to see if it helps but you may not need the whole 1mg (these pills can be cut). If this method with dosage tweaks still doesn't do it, you may need to switch to a different delivery route (such as patch or ring) and maybe even a different form (synthetic versus "bio-ID").

Hope you get some relief soon! I was on an inadequate HRT for over a year and finding a more suitable one has been like night and day.