Had Mirena put in about two months ago, eight months after my second baby was born. On the positive side, the insertion itself wasn't bad and it didn't seem to affect me nursing my baby. But ever since I've had almost constant bleeding and/or weird discharge, increasing extreme crankiness (like having severe PMS times ten), almost no sex drive, tired by lunchtime every day, constantly bloated and gained 5 pounds. Called my OB's office about having it it removed and like many who've posted here, I definitely got an attitude from the staff for wanting it out and couldn't get an appointment for a few weeks. I decided I couldn't stand it one day longer and after reading up about it, took it out myself today. Took me several tries to find the strings but once I got a good hold of it it came right out before I had even really tried and I felt nothing. I immediately felt SO much better, the crankiness is gone, no bleeding, time will tell about whether I will now lose weight too.
Good luck to anyone else who is dealing with problems from it - don't let anyone make you feel bad for wanting the thing out.