Hello Sherekhan and welcome to MM, you've come to just the right place for lots of help and support

I can promise you there are lots of women on here who know exactly what you're going through. and I'm one of them.
Your nasty symptoms are all basically just signs of too low oestrogen, caused by the removal of one of your ovaries, I would assume? You're still very young to only have been getting the oestrogen produced by just the one remaining ovary and hence the insomnia, flushes, low mood, aches and pains. They're all classic signs.
When I hit 43 I noticed that the 10 days before my period was due my mood sank to frightening depths, like you I felt totally numb and blank. At the same time, I noticed that my periods were getting much lighter (but, it can swing the other way for some women, and they get much heavier periods). The depression would only lift after my period had finished, so some months I was only getting maybe 10 good days a month.
Then Xmas 2013 things took a turn for the worse, and I started suffering with intense anxiety, the likes of which I had only ever experienced before when I had post natal depression years ago. I also just felt permanently blank and dead inside ALL the time, not just before my period. This made me suspicious that my hormones were to blame, rather than that I was just having some sort of breakdown.
Since then I have been on a roller coaster, trying various HRT regimes, and seeing various specialists. I would say it's still very early days for you being on HRT, and the effects need a month or two to really kick in.
You will get through this, though I know it feels like you're at the bottom of a well right now. Have a read around on here, nd there are lots of similar tales to yours x