more tiring than anything I have done to date

This morning, (24/12) I went on a 100k ride with a friend, no problem. I felt fine, really still quite strong after the ride. Then a hour later...hit the shops for the last minute shopping. 3 hours of pain. I am home now and I can honestly say that shopping kills me. I would say that 3 hour of standing in ques, looking for THE present (I am 46 trying to buy a correct  prezzie for a 17 year old girl) ie something not "lame " in teenage speak is a lot tougher than a OLY

Tonight I sleep early, cannot wait for that 21k tomorrow morning while the rest of the family is still sleeping