I can only comment on mirtazapine, unfortunately I do not do well on any AD's, had bad experiences with several types many years ago. However, I was so low back in April that I agreed to try mirtazapine, I was put on 30mg at the start, it pulled me out of a black hole overnight, it will def help you with sleep, but after a week I found my panic attacks increased, I did persevere for 8 weeks then weaned off. The only thing that helps me presently is diazepam, I am aware it's not the best answer but at the same time the alternative was being a housebound wreck, they take the edge off the panics helping me to go out and even into town. I also have little or no side effects from those. Maybe give the one you are on another week or so, then if you still feel they aren't for you then change. Sorry I can't be of more help.
CG x