I'm sorry you are struggling to sleep without the Remeron. Sometimes it takes the body a while to adjust to the new chemistry without something you've relied on for so long. Your body is probably still processing the Remeron and just getting used to the Lunesta. The two together could be confusing things. I would maybe give it more time and just expect things to be a bit wonky for a while.

I'd also try working in some natural ways to aid sleep like going to bed/waking up at the same time every day, exercise during the day, or sleep meditation exercises.

I hope this resolves for you soon. I know it can feel awful not getting enough rest.