Don't know of any natural remedies, but I definitely would have in into the doctor to check out what else might be going on with her. I've never heard of a period causing a fever and vomiting or leg pain (I mean, maybe it happens...but seems like something else is going on.)
My only experience is with the Depo shot. Went on at 16, quit having periods altogether. Loved it. Went of at 22 because I hit the age limit for our teen clinic, and didn't have insurance. Pregnant with first child at 23. After having her, went on Nuva Ring (which I also liked, but still had periods, was more of a pain, and now all the warnings, blah blah blah.) So, had my second child (on purpose) in 2010, and because I planned to nurse went back on the shot...which I am still on now. Still love it, still don't have periods on it. No side effects, either, for me...no weight gain, etc.