VAGINAL "FLORA" PH LEVELS

Over the years I kept getting diagnosed with yeast infections. Every single month there's a week or two after my period where my own vaginal mucus makes me very itchy! It's watery, clear, doesn't smell, but there's an irritation in the entering of my vagina and around my labia and it comes and goes. It's not a constant problem. I've read online recently that the PH levels of my vagina could be out of balance making my discharge more acidic, causing the irritation. (Aka bad diet, no probiotics) If that's the case, why would the gyno constantly be diagnosing me with a yeast infection? I just don't understand. Has any others experienced the same?