Devin,
Attitude is the most important thing and you have a great one. In my experience, the fatigue was not a problem for the first half of my 33 rads. Take advantage of each day and do as much as you can. I played golf, kayaked on the lake, walked, and went to work every day for the first 3 weeks before I had to slow down. Set short term goals of activity, such as the next 5 days at a time rather than the 6 weeks of treatment. Also, mentally prepare for dealing with the pain and effects of the rads to your mouth and throat so that you will be able to change eating habits. Example, I progressed from eating soft foods to fruit smoothies and finally ensure shakes. You will need plenty of protein for your body to recover from the radiation damages and healing. Having said all of that, everyone is different and we all recover on our own body's schedule. Also, most important, I had an army of prayer warriors who held me up - I pray that you do too!