Help!!! What is this???

So I’ve had my IUD for a year now(Liletta). And this past months I’ve had sex multiple of times but it is protected with a condom. The last time I’ve had sex was November 21st. Then about a week ago until today, I’ve been spotting. Today before I was in the shower, I spotted and it was a light pink discharge and a few days ago, my spotting was brown. Also I can only feel one string of my IUD. What should I do? I don’t have any cramps at all. Also, this morning when I went to the bathroom, I wiped this off. What is it?