Cramping with Paraguard

Christine
I got Paraguard put in around early July and I've experienced some level of cramping almost everyday since then. I fall in the group of people that has never had a kid (if that makes a difference). I've had sex multiple times since then and only just recently did the guy say he could feel the strings. 
Anybody else have this experience or have any idea what's going on?
How long did it last?