My personal experience of all three: My doctor swapped my Amitriptyline for mirtazapine and I didn't have any side effects at all. I use Propanolol intermittently at times of greater anxiety and cessation has no effect and stopping Zopiclone didn't cause any effect (although I was only on it for 28 days).

I'd go back to your doctor and seek their professional advice.

Good luck

Tony