I had Miren a for 3yrs and 4months. I didn't start having the crazy symptoms until right before the 3 year mark. I had minor things that I had no idea were from Mirena. When the heart beating too fast and feeling major anxiety kicked in, I started to wonder what was going on. Then my left leg seemed to always fall asleep, diiziness and head tingling. It doesn't seem to matter how long you had it in. Once your body has a bad reaction that's it. I read some ladies on have there's in for 6 months or so and feel the same way I do.