I got my mirena March 25, 2015 and I could feel the strings.. My fiancé is in the Army and I came up here three weeks after getting the Mirena and we had sex(doggy style) without a condom. Now I can't feel the string and I'm afraid the IUD got moved around and I could be pregnant! It was this past weekend. I was supposed to ovulate last week and my period is supposed to come next week. I have basically spotted since after it was inserted and still am after sex.