My IUD is falling out!

I've had my IUD in for a few months now and I've only checked the strings once, I know your supposed to after every period but I stopped mine a month after I got it put it. Well last week I checked and my strings we're really low like almost hanging out, I checked again yesterday and I can feel the plastic part. I'm going to call my doctor tomorrow, not sure how long it has been missed placed. Anyone know if the IUD still works if it's missed placed?