L.W.
I use Paragard, which is different in its lack of hormone. However, the cramping lasted about a day and was minor. I was told spotting was normal and that cramping could last longer but could be alleviated with the same medicine you might use for menstrual cramps. I wonder if there is a different depending on how soon after birth it's inserted (mine was about 8 weeks after), but I imagine it could be different if that's not a factor.
Either way, I hope you get relief soon!