Trish - please don't panic. I think there have been studies done about coming off hrt and there were no firm conclusions about what is the best way to do this so simply stopping won't be a big issue.
If you having phytoestrogens like Red Clover and extra soya these do not need progesterone as the effect is very weak, hiwever I believe women who have had oestrogen receptive breast cancer are adviced not to increase phytoestrogens in their diet.
I take REd Clover because there is some evidence that it can help heart and bones and sometimes help to reduce flushes a bit. I suspect my flushes are reducing a bit because my body is adjusting more now ( I am 62) and I am taking life a lot more easily these days - I've cut out as much stress as possible.
The Hrt dose you were given was low dose and they will tell you at the scan whether there is a concern about the thickness of your womb lining - if you have had heavy bleeding or bleeding doesn't stop a few days after stopping hrt, then there might be some concern. Try not to worry.
The amount of oestrogen a women needs will be very individual.
By taking a break from all hormones for a few weeks, this will give you a chance to truly access where you are in your meno journey and how tolerable any meno symptoms you experience are - you can then decide how you wish to manage things going forward.
If your scan is in 4-6 weeks time then this could be perfect as you may feel you simply want them to insert a new Mirena and you can then just add in a bit of Oestrogen as Oestrogel or ‘oestrogen only' patch to control your flushes.
Your GP has been at fault over your old Mirena and he/she is now panicking because it is their lack of due diligence that has landed you in this situation. I doubt there are any real problems, so stop browsing all the various scary stuff on the net and concentrate on a lifestyle with good diet, exercise and, every importantly, regular relaxation and see how things go. Keep us posted DG x