This journey is brutal for some of us....I've been trying different hrt for 6 months now, and am currently trialling a patch & a progesterone tablet regime - lowest dose. I too tried the anti depressant route, and like racjen, found myself suicidal - have never been so unwell in my life.
If you've just stopped the urtrogestan, your anxiety, insomnia and low mood could be like an extreme form of pmt? And you might feel a little better once you start your bleed? I've not started on the progesterone part yet of my new regime (I have earlier this year been extremely sensitive to the massive doses I've been put on!), but it's at a much lower dose than before and I'm keeping a very close eye on myself. I too was getting smashed awake by anxiety attacks at 2am, and have a medication that I take to settle and put me back to sleep, so your idea of using temazepam for that is a good one. I also find eating regularly helps, as does magnesium before bed.
We will (hopefully) all get through this, day by day, minute by minute. Good luck with it all xx