I've had my IUD in for about six months now, and every now and then I would check to see if could still feel my strings to make surely Mirena was still in place. Sure enough I could always feel them. A few nights ago my boyfriend and I were having sex and he fingered me intensely. I went to check my strings the next day and they were not there at all! What could've happened? Did they get misplaced or moved around or did my IUD fall out of place?