Most people I talk to have no idea what I am talking about when I say I am herxing. Here is some information on it--
The herxheimer reaction, nicknamed "herx" or otherwise referred to as Jarisch-Herxheimer (J-H) is a phenomena originally observed in the treatment of syphilis, but later found in other illness. In general terms, it is described as a temporary increase of symptoms when anti-syphilitic drugs (antibiotics) are administered.
Basically it is a worsening of symptoms due to the antibiotics doing their job & killing off the bacteria. The die off of the bacteria causes your body to become "toxic". The kidneys & liver can only do so much to detox you, so I must drink a lot of water and do what your doctor recommends.
It's hard to tell the difference between regular lyme sypmtoms & a herx. So herxing is good. If indeed that is what it is. But your doc does not want you to herx "hard" because it further weakens the immune system