Fishy odor

Why does it smell fishy down there!!!!!!! I have been dealing with this for so long and only one time it ended up being BV. It’s not so much coming from my vagina but more like the sweat that is unavoidable between the lips. 😔 it does get worse the closer I get to starting my period.

I am sick of this and it makes me so self conscious. That being said, I am very careful about my hygiene down there and don’t know what else to do. Any suggestions would be appreciated!!!!!