Yes it's most likely the iud I thought I had a tampon up there so I reached up there and grabbed it. It didn't feel like "fish lining" like the doctor said it feels like so I assumed it was a tampon hanging on by a little thread, so I pulled felt a little cramp and out came my iud at the end of it was looked like just cotton or just little things maybe from clothes but anyways sounds gross but was tangled up at the end of the two iud strings.  Glad I removed it, sounds pretty gross but I mean it's normal. Take your iud out!!!