What Causes Pink Tissue-like Discharge And Abdominal Cramps?

I've had a Mirena IUD in for about a year now. I've practically done away with my periods. I just spot here and there. Over the last week, I've had two occurrences of pink tissue-like chunks on the toilet paper after urinating. There was no blood or foul odor that accompanied it. I have, however, had some very mild lower abdominal cramps but nothing that has been of great concern. A few months ago, I had an ultrasound to check on the position of my IUD after I had been experiencing sharp left sided pelvic pain. The results showed my IUD facing obliquely to the left. My OB/GYN said it was fine but now I'm concerned that it may perforate. I'm sure I'm overreacting but the tissue like substance has me concerned and it will be a while before I can see my OB/GYN as his office is very busy and booked. Any input is appreciated! Thank you.