dibradley, just a few thoughts on your last post. (Later edit - where is it?! Am I imagining things - the following was posted in response to a long post of yours that seems to have gone missing!) I'll leave my reply below in here, though it will make little sense as the one I was replying to is now missing . . !
I'm afraid a resurgence of flushes & night sweats is a common temporary reaction to changes of HRT dose, up or down, so doesn't necessarily mean that in the longer term that adjustment in dose is not right for us. It's a manifestation of the body's reaction to the instability. You may well need 3 sprays (or a different regimen entirely), but unfortunately it takes time for us to settle & be more sure of what is or isn't suitable. We are usually advised to give each dose change or trial of a new product 3 months unless the reaction is such that it feels unwise to persevere.
Testing sex hormone levels in perimenopause is usually considered to be not very helpful because the situation is so unstable, so unless your doctor advises this, I would not worry about not knowing your oestrogen & progesterone levels at present. HRT adjustment is usually made according to symptoms at this stage.
I'm not surprised a 50mcg dose of Thyroxine caused palpitations if your TSH has been brought down to around 3 on 25mcg alone. 50mcg will have been too high a starting dose for you. Adding in more Thyroxine at this stage to try to get your TSH down further may increase your palpitations, anxiety, insomnia, night sweats & flushing as these can be symptoms of too much thyroid replacement (as well as due to menopause - I know - frustratingly confusing this combination of conditions). If your doctor advises increasing your thyroid dose now however - many like TSH to be around or a little below 2.5 - I would talk to her about making only a very slight increase as you will be less likely to become over-treated that way. I don't know what brands are available in Holland but here we have TEVA which comes in 12.5mcg tablets that can be halved to give a very small dose of just 6.25mcg. When making minor dose adjustments we can even add that tiny dose in every other day to be very cautious, then retest after 6 weeks to see how things stand. I'm afraid no one can tell you for sure what is the right TSH (T4 or T3) level for you - it's very individual & may change with time. It depends on what you feel best on.
If you have a B12 deficiency that can cause a range of symptoms, palpitations included & it's really important to address that, so with any luck the B12 injections will make you feel a good deal better.
Most hypothyroid patients, around 85% it's said, do very well on T4 alone. Only around 15% have problems converting T4-T3, so it's very likely you will be among the high proportion that doesn't need to take T3 as well. A good endocrinologist is invaluable in cases where patients don't respond well to T4 alone, but uncomplicated hypothyroidism is usually managed at GP level - at least in the UK. So as you say, private healthcare can be very costly & I think in your shoes I would defer that step for now. If your GP can test T3 that would give you an indication of how well you are converting - that may be possible in Holland, I don't know, but the NHS is usually reluctant to test it here for hypothyroid patients.
There is every chance that given time to stabilise on HRT & thyroid replacement you will feel a lot better - especially if there is currently need for B12 injections, which complicates the picture at present & makes it difficult to know what may need changing.
I would not start zinc supplements at present unless you know there is a deficiency & your doctor advises this, but this is my personal feeling based on my own experience & others may advise otherwise. Please go with whatever you feel most comfortable with. W x

P.S. I see another post has been written while I was compiling this, so I have not taken account of any advice given there.