Hi lilacsophia - You're experiencing a healing crisis, also known as a Herxeimer reaction, cleansing reaction, or detox reaction. These happen when the body is releasing old toxins faster than the eliminatory organs can get rid of them. You can learn more about them by reading articles on the topic on http://www.drlwilson.com
and http://www.arltma.com.
In your case, your kidneys are the organs that are being overloaded trying to eliminate old toxins. Hydrangea root and cranberry juice are good for the kidneys.