constant Odor changes !!

My ph balance keeps changing, every time after sex I get a fishy odor with a yellow discharge, right before my period and now after my period I have an odor. I don't douche with anything but warm water.. I've had BV before and yeast infections...I can't seem to stop this change of my ph. I only wash with unscented soap, I wear panty liners daily, I don't wear underwear to sleep, I shower everyday, etc.