period smell but no period?

February will be one year since i got the Liletta IUD; i’m mesmerized at how amazing and easy it’s been. Oct 10th of this year i had sex w/o condom and he came in me. my two periods after that have been fine. the past almost week i’ve been having an odor that smells just like a period but i haven’t had any bleeding. i am due for my period, the smell hasn’t happened before now and now the smell is gone as far as i can tell. Any idea what’s going on? is my period gone thanks to liletta and i’m just stuck with the smell? could it be an std?; i haven’t had any symptoms and this smell just started.