Kate, sorry to hear you've had the flushes so bad for so long and that you can't take HRT for them.
There are a couple of things which helped with mine.
One was taking fluoxetine (prozac). Within about 3 days of starting to take it, my flushes were less intense. (It wasn't prescribed for the flushes but the Dr thought I was depressed. However, helping with the flushes is apparently a known side effect.)
For me, 10mg was enough to help with the flushes, and there was no benefit from a bigger dose.
The other thing that helped a bit was soy.
(I used soy milk and yoghurt, but of course you can get supplements too.) It wasn't a dramatic improvement, but enough to be perceptible.
With the 2 put together, my hot flushes are now copable with. They were pretty bad, but not as bad as yours. Sometimes I felt like my head was exploding, and claustrophobic like I just had to get out, and sometimes had to lie down. Now that is v rare, mostly when I get them I just feel hot.
But there are also other prescription medications - I havent tried them but I think Dixarit is one. They're on this site in the green menu I think. So you need to see your Dr (again?) maybe. Also, is it absolutely definite you can't take HRT? Cos they reckon most women can, but if you have contraindications your GP would not be able to prescibe it but would need to refer you to a specialist menopause clinic - they even sort out HRT for women with breast cancer I think?
You are having a very hard time with this and you need to insist your doctor take it seriously!