Hallow Dear,
You have two issues, may be interrelated with each other; however should be sorted out separately.
Altered taste or hunger may be a symptom of
pregnancy only if followed by missing a period which is the first cardinal symptom to appear. There is no mention about your period in your history. If you have missed a period, please get pregnancy test performed on your overnight first morning urine sample a week after missed period; earlier these tests may report false negative. If you have not missed a period, these symptoms related to eating habits need not be correlated to pregnancy.
Since your appetite has increased and you are eating more, you might have put on weight which is making feel your jeans tighter. If pregnancy test proves that you are not pregnant, please get your blood examined for Thyroid function.
Thyroid dysfunction does alter the appetite.
Now missing of your intrauterine device: Please take it rather seriously. Missed IUD can lead to pregnancy.
Ultrasonography will show the position of the IUD. If it has perforated the uterine wall - partially or completely, it needs to be removed by some intervention.
Please report to your Gynaecologist ASAP.
I hope tis provides you guidelines on your query.
Dr. Nishikant Shrotri