Yeast infections that keep coming back

Hey everyone, I need some advice. I'm gonna go see a doctor this week because this is beyond ridiculous now. I keep up good health and keep her dry. Eat the right foods including heaps of garlic because I read on the web it can help repel it but around this time every month for the past 4-5 months now it's been coming back. I use the cream and even done a PH test and it was fine but I don't understand why it keeps coming back, like I said I'm going to a doctor this week but yeah. Any of you ever have to deal with something like this? I'm 17 by the way and also sexually active. I know I don't have any stds and that my partner is fine. What you guys think tho?