Mirena falling out.

Has anyone had their mirena become displaced or even completely fall out? I'm pretty sure mine is falling out.. sure enough that I called my OB and have an appointment in the morning. Just wondering if anyone else has experienced it and if they had any soreness or discomfort. Also wondering what was your clue that something was wrong? Last week, I had abnormally heavy bleeding. Then the past few days, it felt like I had a dry tampon left inside of me. This afternoon, went to wipe after using the restroom and felt the string tugging on the toilet paper. Will I be able to get another IUD placed immediately?