@magscratch Radiation fatigue is a very real side effect - the body puts out a lot of energy to repair those cells impacted by the radiation. So even though you can't see or feel it, you're actually exerting a good deal of energy so that fatigue is a call to rest and recharge. And to do that your body also needs the right type of nutrients so that's an especially good step you're taking with the nutritionist.

Mayo Clinic has a lot of information on best practices for rest and nutrition during cancer treatment. I found a specific one for radiation here: https://www.oregoncancer.com/blog/eating-well-during-radiation-therapy

Let me know once you've turned a corner on this, it may very well be after that 5th or 6th treatment but the end is in sight!