You can try taking 'optizinc' which is supposed to not displace copper so wouldn't create as bad of a detox effect. i would assume that zinc is displacing other nasty metals which are then flushing out of your body. I had that happen to me too for awhile but now I can take zinc without any effect.
I would assume that this is part of your healing and a good thing. Only other thing I can think is that zinc is lowering your sodium, you could add a little Sea Salt to troubleshoot. Good Luck.