moonbeam - I am sorry to say that I think your GP is not a specialist when it comes to HRT.
You do not have to take the oral HRT.You don't have to do what the GP says.
It is your body.I don't know why do you continue to do so when you have stomach problems? As Cazikins says it has already been said many times on here by lots of us.
I appreciate it will come as a shock that you cannot put your faith in your GP and they are not infallible but this has happened many times to women on here - GP's are generalists, not specialists and they are sometimes wrong when it comes to menopause.
You have come on here asking for advice but then disregarding it.
Even if you are not convinced that the oral HRT is causing problems - the fact that it recommends on here by Dr Currie, and elsewhere that transdermal (patch or gel) HRT is better for anyone with stomach problems should convince you that it's not worth the risk.
The headaches you are getting are a different issue. It sounds like the sudden increase in oestrogen is causing you side effects. This is a common problem and again transdermal HRT is recommended for anyone with migraine type headaches. If they continue you need to get them checked out.
Someone else on here had problems with oestrogen and maybe headaches and started off with a very low dose and gradually increased until she could tolerate a higher dose quite happily. Maybe you could try this. Cut the 50 mcg patches in half and try half a patch (or even less) for a week or two and then gradually increase. The woman on here used to even cut a bit off the half patch and increase ever so slightly.
We know the doc was wrong because they said that there is not a higher dose but there is remember:
http://www.menopausematters.co.uk/treatafter.phpIT mustbe difficult in your position especially after your operation and I repeat - ask to be referred to a meno-specialists - look on the map here and see if there is one near you
http://www.menopausematters.co.uk/clinicfinder.phpIt sounds like your doctor is not helping you.
I don't think I can help you any more as I've said everything I can think of with your problems and i hope you get them sorted out soon - but please listen to our advice if you are asking for it.
Hurdity x