It might be your diet. Also how you wipe. As silly as it sound make sure you're wiping front to back because if you do the opposite that can be a factor.
You could also try to add more garlic to your diet. 2-3 cloves a day for one week. If that doesn't make it better than move on to another option. I have also heard of inserting a clove into the vagina over night for 2-3 consecutive nights, but in my opinion it sounds a little more risky and somewhat not worth possible side effects. Google it and see what I mean.