Nancy,
It is wise of you to be researching and asking questions, of both your urologist and others. Concerning the reduced dose, I believe that this is done if your reaction to the full dose is too severe. Each person has to decide for themselves how much of a reaction they can handle. For myself, I have decided that if the dose is tolerable (even if uncomfortable) then I will continue with full dose. For me, reducing the risk of recurrance is more important to me than reducing my discomfort. But, again, everyone has to decide these things for themselves.
My own reactions to the full dose (81cc) have been a feverish feeling on the evening of the treatment, and bladder spasms until evening. I have found that eating and drinking nothing from two hours prior to the treatment until my first voiding (two hours after) has helped ensure that the treatment impacts my bladder as expected (debris and blood during the 6 hours after my treatment). For the first three treatments, I was taking large amounts of water immediately after receiving the instillment, and feel that this may have diluted the treatment too much. I now hold off drinking until after my first voiding, and drink 13 ounces following each voiding there after. This seems to help clear out my bladder quickly, and I believe to reduce what could be greater reactions. Like you, I do feel very tired the next day, and sometimes am still a bit drowsey the day after that.
Keep in mind that Tb in your bladder triggers your immune system at many levels, which is exactly what helps kill any cancer that may be developing there. Just like any bacterial infection, your body will get exhausted. If your body's reaction is too subtle, then the treatment may not be causing the desired result. I am encouraged to hear that your body IS reacting to the treatments in the manner you describe, as that seems to fall well within the desired results noted in Dr. Lamm's protocol.
Concerning the schedule, it appears that the regimen you are on is what is called the SWOG protocol, which is recommended by Dr. Lamm, and seems to be the most widely used. At the bottom of the document (linked by Patricia), you will find a summary of the schedule, which has helped me to plan ahead for what is to come.
Lastly, hearing about your experience after three rounds of treatment is encouraging to me. I just finished up my 6-week initial treatment, and have my next Cysto mid-May. At that time the urologist will let me know what will be the next step (he seems to be trying different regimens with different patients).
Be encouraged!!