Anyone familiar with mirtazapine?

Is anyone very familiar with mirtazapine for sleep or anxiety? I have been taking 3mg lunesta every night as instructed by my sleep neurologist. He thought that I was so concerned about my insomnia that I might need anxiety medication. Especially when I started waking up in the middle of the night and couldn’t get back to sleep. To my surprise he prescribed mirtazapine. 15mgs, take 1 or 2 pills with lunesta every night. The first night, I took 1 and had blurry vision and felt somnolent and generally lousy all the next day. The GP said cut it in half for 7.5 mgs. I still had the same results. The next 2 nights I took half of the half, 3.75 mgs. Still same results. After 2 days of only lunesta, no mirtazapine, my vision is almost back to normal and I’m feeling somewhat better. Does this sound familiar to anyone? Could this be a problem with the half life of mirtazapine?