Kyleena symptoms

I got my Kyleena iud on December 9th, and it cramped a bit the first days and then it disappeared for a bit. Now I've been spotting ever since which I think might be normal, but I also missed my period this january 1st.

My main problem is that my cramping is coming back, not so that im in constant pain but it feels like someone is pinching my uterus and then letting go. Is this normal?