IUD?? 😨

I've tried a few different forms of birth control now and my body is just not having it. I've talked to my doctor and she talked me into scheduling an appointment to try an IUD, let me be completely honest. I'm so nervous. My older sister swears it's the worst thing ever created. She thinks it can move and cause major issues. I'm trusting my doctor but any of you girls having the same issue? Had one didn't like it? Have one and love it? I'm just a little worried..