Can't feel IUD strings

Need some IUD advice! So I (19F) have had an Liletta IUD for over a year now. Usually, I can feel the strings but when I checked I cannot feel them anymore. I am ovulating so I know my cervix is higher compared to right after my period when I should be checking. I'm getting an ultasound Friday to check and I'm pretty sure they just curled up. But has anyone else had an IUD for awhile and then suddenly can't feel the strings? Just looking to ease my mind