Help 🙃🙃

I’m currently 12 days late! I started on Nov 20th and finished on the 25th of November and I didn’t get a period for the whole month of December has this happened to anyone ? Definitely not pregnant as I’m in a same sex relationship the only difference I did in December is take prenatal’s because we’re going to do IUI in February but I’m almost positive the prenatal’s didn’t mess with my period, has anyone else ever skipped a month for no reason at all??