Mirena iud?

I’m 4 weeks postpartum and am starting to think about birth control. I’m breastfeeding and I really want to continue. My doctor told me my options are the mini pill or Mirena iud. I wanted to take the mini pill but she says it’s only 90% effective when taken perfectly and that scares me as I CANNOT have another baby for a few years. The iud sounds great but I’m terrified of getting it inserted! I hate the thought of having something implanted in me and left there. I got an iud when I was 16 and it didn’t work out. I don’t remember why but I had it removed. I hadn’t had a child yet so my dr says it’ll likely work better for me now. Please share your Mirena stories.