Normal is whatever it is for a specific person and how toxic they are. Detox symptoms can vary from mild headaches, some body pains. light nausea to all out migraines and get on your knees pray to the porcelain god kinda thing. It will all depend on the individuals condition. Many either breeze through it or just have mild symptoms.
I breezed through my first and second MCs (40/28) and my most recent (40) dayer that I just finished last week but on my 3rd 21 dayer I had an all out knock out drag out on my knees vomiting and nausea round around day 17. I just sucked up and drank lots of water and was fine the next day.
The wisdom when going through detox symptoms is that it actually is a good thing that your body is releasing toxins and the first line of defense is to just start guzzling water to keep the toxins diluted and moving out. While Mr. Burroughs (originator) is dead set against enemas many folks have gotten instant relief on s detox crisis from doing an enema.