Sorry to hear this donnacrichton.
I really don't know how to help and think you need some specialsit advice. If you have no ovarian function, as I think we have said before, 50 mcg is not a high dose at all, and it is usual to increase the dose of oestrogen to a level at which flushes cease - at least at the very minimum. For instance I came off HRT a few years ago and after 3 months all the flishes were back so doc put me back onto 25 mcg (aiming to reduce my "dependence"). This worked for while but still had some flushes so went back up to my original dose of 50 mcg and they went. Even when I reduced to 37.5 mcg a couple of years ago after some investigations, the flushes started to return. I am very surprised that even though you have flushes on 37.5 mcg, you get a headache that persists after such a small increase. You would not expect flushes due to an increase in oestrogen and really ideally you should be able to tolerate 50 mcg. If you have no ovarian function then you are presumably lacking in testosterone too? It could be that the headaches are caused by lack of this - maybe exacerbated by the increase in oestrogen? I don't think this is well understood. When I went to see Annie Evans she said that lack of T often caused headaches, I have definitely had fewer migraines recently since taking T (since May). Can you get a referral and ask to have some of this? Then you might be able to increase the oestrogen without headaches? Just a thought.
Hurdity x