your experience with mirena iud

I just had the Mirena IUD implant and now I'm cramping (for 3 days) is this normal? I read online that there have been a lot of lawsuits against Bayer, the company that distributes Mirena. Should I be worried? I just feel cramps but I'm getting scared because what I have read. Please tell me about your experience and if you've ever ended up pregnant despite being on this type of birth control.
I was told this is the best long term option for breastfeeding instead of the mini pill which I would most likely forget to take