I'm almost at my one year since removal date, Feb. 9. Last night I took a Zanex .5mg for anxiety. It happens less and less frequently since removal, but it still happens. It is always 2 days before my period starts, then I'm fine. My doctor prescibed only 20 pills back in August and I still have a few left. I did not want to be medicated all the time. For some reason, my anxiety only occurs at night, around 6 or 7pm. So I know I can take one about 8:30 and then go to bed for the sake of my family. (they do make me tired or I wouldn't sleep all night - I've stayed up 36 hours straight when the Mirena was in and I was at full blown anxiety/panic attacks, many nights). I truly hope that all of your issues with the Mirena will decrease with time, as mine did.
I don't think anyone can put a time limit on how long you will feel bad, each of us has they're own story. Just know you will get better and please ask your doctor for help if you need it.