I would first like to say that I am not an expert on this. This is only my second fast and I have never experienced the symptoms that your are describing.
I have, however, done a LOT of reading on this forum during each of my cleanses. Several very experienced cleansers have said that you should try not to end your cleanse on a low note. It is suggested to fast through a "crisis" and let your body get rid of what ever is causing the problem.
I personally think that your body is really trying to get rid of something nasty and that you should try to let it do its work if you can. Considering your symptoms, however, I could not blame you if you stop.