Exam and my running nose

Our examination was scheduled to be finished at 28th April, but postponed till 4th May. I got a running nose from 2nd May. My friends said "What a bad luck ; it apparently didn't find any other time to disturb you." I answered "It's not the fault of the running nose. It schedule itself to be happened after 28th. But our exam got postponed. What can it do?". My friend exclaimed "What a logic"!