You need to have your IUD checked! If you aren't near a MTF that has an OB/GYN clinic, call your PCM and get a referral asap. Do it before you move so you aren't worried about it and have to deal with it over the holidays. Tell them you need an appointment asap because you are moving and are going out of town for the holidays. Put some urgency in your voice and tell them you are in pain. If they can't make an appointment for you before you are supposed to leave, then go to the ER and deal with Tricare later.
You know your body better than anyone else and it's trying to tell you something. If it turns out to be nothing then you will be relieved, but if it moved or is embedded you could have some serious consequences. Follow your instincts and get it checked by a GYN.