Sickly sweet vinegary smell coming from cm

Amethyst
Okay I really would like to no wat this means and I really don't want to go to a doctor. I currently have the nexaplanon implant in my left arm. My SO and I had unprotected sex on the 28 of July and two days later I received my period. Nothing has changed in my diet so I'm really curious on y this smell showed up a few days after my period ended would love to hear from anyone with info thanks!