I'm glad you've been able to get a quick appointment which hopefully will be successful and get you the type of progestin you need.
I sympathise, my GP has lied, explained
she has to lie to women because they don't understand (Yes, she really said that when confronted!) and she refused me medicines which she is allowed to prescribe for no good reason at all.
When I tried provera for example, I was as ill as I've ever been in my life, not just physically incapacitated which was bad enough having to take time off work, but I fell straight into a suicidal hole that I couldn't see out of. After three days of this I got through to my GP and told her I was planning my own death and could think of nothing else but how to tell my kids I needed to die. She told me that wasn't a side effect and I couldn't switch HRTs until I'd given it a proper trial and I'd done less than a week so far, I wasn't even trying.
I asked how long, through my sobs, she told me 3 to 6 months, I told her no way would I be able to fight it that long, I'd be dead by suicide, she reminded me again about how progesterone intolerance doesn't happen in menopause, it must be something else, changing progestins won't affect me, silly me

There was no sign of the doctor having any feelings or emotions other than impatience.
I stopped taking the provera pills and was labelled as non compliant for that, but I started feeling better immediately and found that I very much want to live as long as I keep away from provera, utrogestan, cyclogest, levenorgestorel, norethisterone and whatever it was in the mini pill when I tried that too.
I had to do without the oestrogen, but I didn't notice it doing much, so I wasn't bothered.
Of course my doctor must be right, always, so now she hates me and tbh it's fairly mutual.
I was left with no HRT until I got tibolone off a locum and I've never looked back. They say it's safe, the leaflet is meaningless apparantly and tibolone can safely be given "to anyone", I guess they mean any menopausal woman. I've high blood pressure and that's ok. I've been on it over a year now and they don't even do any checks after you start it, not unless you feel unwell and pester them. I had 11 episodes of bleeding in the first year, each lasted five days, they aren't interested at all in that, 20% of women have fake periods on tibolone, I must be one of them, I don't need to keep telling them about it.
I hope I can stay on it forever.
It works to make me feel better, more alive, younger, more alert and energised, but I still have maybe 10% of my hot flashes, mostly because I won't quit coffee!