WHAT JUST CAME OUT OF ME?!

I’ve had the Mirena IUD for about 4 months and I haven’t really had spotting or problems but last week I started getting weird cramps in my lower abdomen and in the shower all this gross gunk keeps coming out of me when I go to clean myself. I’ve been to the gyno on campus and she said it’s in the right position and stuff but this is freaking me out.