Horses,Horses
The GPs are often the worst place to get advice about treatment for meno symptoms. There are menopause clinics in many areas around the country and there is no reason why your GP shouldn't refer you to a gynaecologist for further advice if you want.
I think there is a link somewhere on this site about specialist meno clinics - it depends where you live as to what is available. If you are in or near a big city there should be something.
So sorry to hear your sister had breast cancer so young - can you find out whether this cancer was oestrogen sensitive? Some breast cancers are and some are not and this may determine whether you are at risk or not. Again you need specialist advice about this.
You talk about having 15 years of this - well that isn't really the way to look at this - your symptoms may settle down in a few years or they may go on the next 20 years or more. None of use know how long the meno symptoms will last. In the long term, even if your flushes etc calm down quite quickly, without HRT you may get more problems with vaginal atrophy, bladder issues and bones. Having said this, my mother had a premature meno, didn't have any HRT (so was really cranky through my childhood ) but she is now 86 and is basically quite healthy, though has shrunk by about 4 inches.
You need to look at your current state and how you can achieve a good quality of life for not only your sake but for your children and husband. Clearly you are struggling with anxiety (which is a classic meno symptom) and it is amazing how negatively the lack of oestrogen impacts on our bodies - many of use struggle with gastric issues with the meno. At 58 I am going to try going back on HRT as I need to work for the next 6-7 years and the meno symptoms are getting in the way of this.
My advice would be to get as clued up as possible, ask for a referral to a meno clinic or gynaecologist who specialises in menopause for some proper advice and do look at this website:
http://www.daisynetwork.org.ukGood luck. Dg x