I can now safely say that I'm doing much, much better. I don't know if I can say for certain that the side effects are completely over, but the worst has definitely passed.
The pain has been unnoticeable for some time now although it flared up when Gozer launched herself off of me using the radiated area (we were at the vet's and she was sitting up on me with her butt on my neck; when she jumped off, one of her back feet was in the area of the spot and she pushed against it). As quickly as the pain flared, it disappeared.
Fatigue-wise, I'm doing great. I'm waking up feeling well-rested both in the morning and after my naps, and my naps are back down to a reasonable length. I've always been a napper so having to take naps each day is normal. What wasn't normal was having naps lasting hours and hours long and not feeling rested afterwards but all that is over.
I'm also starting to feel engaged in the world around me. Since treatment I've been feeling somewhat depressed and uncreative. I felt like the world around me was grey and dim and that time was just passing me by. Now I see colour!! I'm excited to see the sun and to see what each day will bring. With the lifting of my depression I'm also starting to feel like I need to start creating things. I look at inspiration pictures and I actually feel inspired to design and make things. This is so exciting!
So yes, whether all the side effects are over or the worst has passed, I'm feeling good.