You are experiencing Herxheimer's Effect (you can google that), but you don't have to.
Please check on this link and scroll down to "What detox methods worked best?. It's a long post, but the ideas in the detoxing methods should help you. The number one thing to do to get rid of all those floating mobilized toxins is a detox bath. I describe that as one of the methods. Being low in magnesium will make you irritable and have lots of other negative symptoms. //www.curezone.org/forums/fm.asp?i=1032518#i
Also, here's a link to a 5-minute description of symptoms of low magnesium (they will sound familiar to you) and what to do about it. The script is written beside the video window, so you can easily copy n paste the most useful info:
Don't give up! The longer you can do the MC, the better your results will be in the end. If it is too much for you, you can always stop, take a week or two to prepare (focus on drinking soups and juices, freshly squeezed/pressed is best) and then start again. I found this to be really helpful for me, as my body got used to living on a liquid diet, and I didn't have to deal with the cravings for solid food.