Vagina yeast infection, candidas glabrata: im on fluconazole 300mg/day for 3 days. my period came. period alters the ph value of vagina, will it ruin the good works of fluconazole? my previous yeast infection got better but came back after period?

As discussed previously, probably fluconazole will not be effective. It may be worth a try, but most likely a different medication will be necessary. In any case, altered vaginal pH (due to your period or anything else) will have NO effect on how well fluconazole works. (When it came back last time, it wasn't because of your period. It's more likely because the treatment failed.)