I have been on mirtazapine for just over a year. I was having severe cyclical mood swings\pmdd. Initially my GP said to take it (half a 15mg pill) just on the week prior to period. However i found it so successful in helping me sleep I stayed on it all month, with my drs knowledge.
I will say when I first took 1\2 a tablet, rather bizarrely I stayed awake all night and slept during the next day.
So the next night I tried a 1\4 tablet, about 30 mins before bed, and it worked. For about 3 weeks I did feel zombie like in the day, but my body adjusted to it. I have heard some say that smaller doses seem more successful than a larger dose?
So, for me the 1\4 tablet worked well on my horrific cyclical moods, and benefits my sleep. It may be worth trying taking it at different times? It does take a while for the affects to work.
Incidentally, I also take amitriptyline, for fibromyalgia nerve pain. This is also used primarily as an antidepressant \anxiety med. Again, I have had to wiggle the times I take this ( several chronic health conditions means I have to space all my meds out ). I take the amitriptyline 3 hours before sleep to avoid the zombie affects next day.
I never accepted oral progesterone, the huge hormonal fluctuations were a nightmare for me, and opted instead for the mirena coil, felt hormones were more stable in a way. I was never expecting a total 'cure ' with hrt, just a better support form it. Fair to say perimenopause for me was diabolical.
I wish you well.