I had the opposite experience.
My experience, also, happened during the longest days. In 3 days, I basically did nothing but fish, sightsee and fish. I figured if there was sunlight, I should be fishing or sightseeing.
After 72 hours of the fishing and sightseeing and no real sleep, I became catatonic for about 24 hours. After that I limited the fishing and sight seeing to about 16 hours per day.