Recurring yeast infections.

I had my first yeast infection EVER about a year and a half ago, took a pill from my doc to clear it up, and was fine, but since then, I've been getting them every couple months. I've just been treating them at home with Tea Tree and Lavender essential oil mixed with some non-scented body lotion, but why does this keep happening? The only thing I can think of is that I've been wearing leggings almost every day (became a LuLaRoe consultant a little less than a year ago) instead of jeans like I used to, so the tighter pants might be causing yeast to grow. I really hope that's not it though because I LOVE me some leggings!