I Used Mirtazapine For A Week, 15mg Every Day Before

I used Mirtazapine for a week, 15mg every day before I went to sleep. It was a year ago, I found I got restless legs one nice and I stopped it, since then, I found that I got shaking or twitching a lot when I was falling asleep or before i wake up automaticlly, it could happen to any part of my body, toes, fingers, legs, arms, shoulders, necks, eyes, tongue, forehead torso, just twitch liek a lightning, I am pretty sure it casued by some antidepressed medication, but why and is that going to end someday? or my brain got a permanant injury ? thank you for your help