Women with IUDs

I know I recently made a post about this, I guess I'm just overly worried. I got an IUD inserted on Tuesday, since then I've been cramping and bleeding(not too heavily). But I had sex today with SO and afterwards I had theee worst cramping ever. I checked and I could still feel the strings so I'm not sure why I cramped so much. Anyone else cramp after sex? And if so did it go away with time or do you still cramp?