Iud help

Hi, so I recently got an IUD. Immidietly after I got it implanted I put in a tampon, I later read that this was not supposed to happen?? Also when I felt for the strings I could only feel one, about half the length of my pinky finger. I’ve been having unprotected sex with my boyfriend since 3 days after receiving it. Should I be concerned about pregnancy or an incorrect implantation?? Any support would be appreciated!

Edit: it’s a copper iud and I got it on my period and had sex during my period