Good for you girl20.
The general public, and especially conventional Doctors, are usually totally ignorant of the health benefits of water fasting; considering Doctors spend less than 4 weeks out of their total 6 year training on nutrition, (fasting being a state of nutrition) this is hardly surprising: and illustrated by your Doctors comments that you will die and have organ failure. The mind boggles.
Consider the case of Dr Tanner.............
"The statement is sometimes made that after his forty-two days fast in 1877, Dr. Tanner was in such bad condition he had to be placed under medical care. This statement is very misleading. Dr. Tanner had been in very bad health for years preceding his fast and undertook the fast to recover health. He was under the observation of a physician through the whole of the fast and thereafter for some time. He actually regained his health by and through the fast.
Dr. Tanner occupied a room in the home of Dr. Moyer, in Minneapolis, Minn., during this fast and was attended daily by Dr. Moyer. According to his own testimony he "had given up hopes of ever regaining what might be called normal health" and undertook the fast only after he had "virtually collapsed" and "was at such a low ebb physically and mentally that" he "did not care whether" he 'lived or died" and "determined," as he says, "that, since my drugs gave me no relief, I would starve myself to death ere I again would suffer the physical misery that had been mine for months preceding."
At the end of ten days of fasting all symptoms of his disorder disappeared and Dr. Moyer attempted to induce him to discontinue the fast. Tanner persisted to the end of the forty-second day. His health was distinctly improved.
His medical colleagues refused to believe that a man can go so long without food, so, "in order to relieve myself," he writes, "of the odium heaped upon me by the medical enemies" of his claims to have gone without food, in 1880, he underwent another fast of forty days beginning June 28, and ending at noon August 6. This fast was public and observed by many medical men and the whole story flashed to the world daily by the newspapers and telegraphs. Tanner's health was not impaired by this fast."........
http://www.soilandhealth.org/02/0201hyglibcat/020127shelton.III/020127.ch23.htm
Before you do begin your 21 day fast girl20 I would do as much research on fasting as you possibly can to ensure you conduct it properly, especially the breaking of the fast..........
http://www.soilandhealth.org/02/0201hyglibcat/020127shelton.III/020127.ch30.htm
AND....The Hygiene of the Fast.....which should answer your questions in the latter part of your post.
http://www.soilandhealth.org/02/0201hyglibcat/020127shelton.III/020127.ch29.htm
Regards
chrisb1.