This just gets more boring, I'm afraid.

Monday to Wednesday everything was fine - no headaches, no nausea, are they giving me the real radiation?  By Wednesday evening I was quite tired, and on getting up Thursday morning I was completely shattered.  Thursday and Friday I managed to check my email but not actually do any work, and I'm still fairly tired today even after 11ish hours sleep.  On balance I think I'll take the tiredness over nausea and headaches

I am definitely losing some hair now.  I thought there was quite a bit in my hairbrush and on the floor where I tend to stand when brushing it, but then a good bit came out when I washed it this morning.  There does seem to be plenty left, as I can't find any huge gaps yet.  (I will only be losing hair in a band around my head roughly at eye level, i.e. only where the beams go in and out - the rest of my hair will remain, and so cover any loss.  It's likely that where I do lose hair, it'll be patchy rather than completely bald).  Of course there will be pictures, once there is something noticeable enough to show you

But half way there now, so that's all good.  Just wait and see what side-effects the next week brings!