I feel like my IUD is being expelled... help

Basically, I’ve had the Mirena IUD for 5 years, got it replaced in late August, was fine for a while then had a few months of non stop spotting. I went to the doc a couple weeks ago for the spotting & he said everything is in place and my body just had to adjust; since that appt, my spotting and bleeding completely stopped. Buuut, yesterday I started getting a very deep, low pelvis pain, and what feels like pressure on my cervix (only way I can think to describe it). I literally am scared to push when going to the bathroom cause it feels like my IUD is about to be expelled, but I felt around up there and I cant feel any plastic or anything. Has anyone else felt this kind of pain before? It goes in and out, not constant.