Thanks, Hobie.
I had a very painful, stiff shoulder in the middle of last week - it's apparently a known after effect of being inflated with CO2. That kept me awake for a couple of nights with only strong painkillers and a hot water bottle giving a few hours of respite. Luckily, that's now eased considerably, and last night I got the most sleep I've had for over a week.
I stupidly went straight back to work last Monday. I initially felt OK, but by the end of the day I was exhausted. Tuesday I did less than half a day, and then I gradually built up to about 80% by Friday. This week I'm back to normal hours, so fingers crossed I get on alright. I survived today!