Mirena IUD

Hi ladies, I just had my first IUD put in on September 29. I got the Mirena. I just had sex for the first time today since getting it, 5 days after, and it was painful and now I am spotting? Is this normal at first, and if so will I always spot after? I have super high anxiety that it’s going to get attached to my uterus so any little thing worries me. My boyfriend and I don’t plan on having kids until we are married so I hope it’s not always painful. Letting me know your story will help! 😊