What Causes Abdominal Cramps And Vaginal Discharge Post IUD Implantation?

I have had a copper IUD since January and have had no problems locating the string when I check once a month. Today I started feeling light cramps (my period doesn't start until the last week of the month) and have lately noticed an unusual (sometimes bloody) discharge. I checked for the string, as I do every month, and it was not in its usual place. I eventually could feel it, but it was much deeper than usual and off at an angle. Is this something I should be concerned about?