Baffling Pelvic Query

I cannot find much information available on this subject. I'm a 24yo female, married. My husband has been my only sexual partner. Within the last year, my public hair has quickly changed from light blonde (which it previously has been since puberty) to half blonde/half DARK black. The black portion is around the labia and the pubic mound remains blonde. It's changed back to completely blonde twice but intermittently goes back to half and half. It isn't a cleanliness issue. The only information I can find references previously dark hair turning blonde or change as a side effect of menopause, neither which is my case.

Since getting married 2 years ago, I have had several UTIs. I started using Implanon in 2010 for acute menorrhagia that was causing hospital admittance level anemia, which is now mostly under control. I occasionally have irregular, frequent and/or heavy periods. I have major anxiety as well as bipolar disorder and have been on many different medications for both since 2007. I don't know if the color change is due to a hormone imbalance or just a normal part of being a woman that no one seems eager to talk about. As long as it's not an indicator of an underlying health issue, it's not a problem apart from looking like Cruella DeVille from time to time.

ANY help or push in the right direction would be much appreciated. Thanks.