My cervix is a jerk!

I know that sounds really weird but my cervix won't stay in one place. It is constantly moving up and down and while on my period it is really low. Sometimes it pushes out my tampons, and that's painful. So I decided to go with a mental cup. So now my cervix is so low when I put in the cup, the cervix is past the seal unless I leave most of the cup hanging out. Ugh. Anyone else have an issue with theirs moving? It's not exactly normal for mine to be doing this but it does. My gyno isn't worried about it but it drives me crazy!