It sounds to me like she needs to go to a hospital. Immediately.
I rarely post on CZ and I am not a fasting expert, but I feel compelled to reply to your post because no else has yet and, based on your post, I feel that your friend is in serious danger.
I don't mean to be alarmist, but people do die from fasting. I hear this false sense of energy or euphoria is a common effect of starvation....