Sounds like medications aren't working for you. If you think it's due to depression then look into psychological therapies (I guess you could consider discussing an increase in Mirtazapine to 45mg).
Ensure you're following good sleep hygeine recommendations:
www.nhs.uk/every-mind-matters/mental-wellbeing-tips/how-to-fall-asleep-faster-and-sleep-better/

Otherwise consider some sort of sleep therapy / cbt
eg:
www.sleepstation.org.uk/
info.sleepio.com/suitability
( 2 Can Chunder Word to your mums — I came to prod bums, Wed 4 Nov 2026, 12:23, Reply)

This has been happening all my life
I've tried pretty much everything
( Smash Monkey lowering the tone of the whole internet, Wed 4 Nov 2026, 12:44, Reply)