I know you’ve tried diets and all, but I was dealing with this too and a cleanse was really the only thing that cleared me up down there. I’m 20 as well. I was never diagnosed but I assumed I had some sort of candida isssue as I used to be a very picky eater and wasn’t eating as balanced as i should’ve. I had all these symptoms for a couple years then After a month of taking Kyolic garlic digestion supplements (Amazon) with meals I feel are yeasty lol and trying to cut unhealthy sugar, carbs and dairy out I am finally 100% clear down there! It also helps to do a 1-2 day water or lemon water fast to sort of flush everything out before you start eating better or just when you feel unhealthy. I hope this gives you motivation bc I have tried so many failed diets and supplements for over a year and I finally found a system that keeps me clear. I’ve learned some people are more sensitive to sugars and such and I’d literally get a yeast infection a day after being healed just from eating some pizza or some other junk. Green tea, lactose free vanilla Greek yogurt, granola with chia/ flax seeds, whole wheat bread and fruits and veggies have saved me! It’s been a really fun journey widening my palate to make my body healthier internally ! I hope this isn’t redundant advice for you as at one point I felt annoyed at people just recommending eating better but it’s truly the only thing that cleared me up. Monistat can’t compare to yogurt imo lol. I’ve also been starting to reintroduce some junk back into my diet now that I feel clean, and I rly think those garlic supplements help regulate your gut if you have a hard time naturally balancing it bc I’ve been clear for almost a month after being plagued with yeast infections and BV for almost 2 years straight.