I can relate to you when it comes to the yoyoing and wanting to put an end to it this is a great forum for support, the people here are very helpful and informative. Its not a good idea to take vitamins and i've learned on this forum that your body will supply you with everything you need during a fast. You can go on with your life normally and exercise, i exercise on the stationary bike for 45 minutes (havent in the past few days getting lazy :p ) and it feels great.
Good luck