So, after a whole week off and an incredibly long day yesterday, I opted to try the next run instead of going back. Surprise surprise I did it, despite not wanting to and feeling meh. Big improvement from not managing a minute at a time! Run 3 is due for Sunday... we'll see what happens, but I'm pretty sure the hurdle is psychological rather than physical.
Also, delicately, is it me or does anyone else need the bathroom right after they run???