When you're into a heavy training plan have you noticed that it's the small things that can break you. The next run, even if it's a nasty one, can take care of itself but if something small is not in place it is that small thing that you can't cope with!
For example, I have a routine for commuting to and from work by running or cycling. Yesterday part of the routine failed in that I forgot my key pass so I'll have to ring the doorbell when I get to work. This is stressing me out more than the 12 mile progression run I'm doing first!
I've noticed that it's like this in life too. I can cope with my Grandma passing away and so too, I believe, my Dad can cope. But it's the small things like stopping the junk mail from being delivered to my deceased Grandma which is stressful.
I think I know why this happens, but still the mind can seem to be a strange thing.