Ok so maybe it seems obvious with hindsight but yesterday I didn't think twice about doing Wk3 run2 in the morning (and I totally nailed it, finished with loads of energy and feeling great ) on the day I had a 7pm appointment to give blood.
I felt fine at the donation, felt fine after the donation whilst scoffing biscuits and being v.pleased with myself for saving lives. Then this morning I woke up and it feels like every muscle in my body is aching. I guess removing some blood whilst muscles are recovering from exertion is not a good idea!
Think I'll take an extra rest day before run 3 and finish the week on Friday... and make a note not to run on my next donation day in June.