i am a candida sufferer and i have been through many horrible die off periods in my cleansing and recovery. the body goes though several....many, many....until it is able to get enough of the yucks out to heal.
i just emerged from an intense three month long die off, during which i had all of the same symptoms as your daughter. it mimmicks many different illnesses. whatever you do...do not put her on Antibiotics .
make sure she is taking 1000mg of ester-C (vitamin c) a day and taking olive leaf extract in high amounts....it is a natural Antibiotic and antifungal. it works. your daughter's who sinus and gastro-intestinal system is wretching to get rid of the candida and the toxins it causes....don't suppress this with medicine....this is a key portion of the healing process. she has got to wait it out.
the three month cleanse i just endured was hell, but i feel so much more human now.....i was using "primal defense" which i hightly recommend.
i also recommend the book "the body ecology diet" this has made all the difference for me.
you are doing the right things.
many blessings to you and your daughter.