I love being on call and love night shifts too. Though I am currently in a non-clinical research environment, I was (still am) one of the weird night owls.
As part of my surgical training in the UK, where we had to do 6 months of ER, and I chose to do a whole month of nights (quit ER and moved to Urology after 3 months). My longest continuous on call periods have been 57 hours in the UK and 12 days before that in India.
The way I see it is we as doctors are one of the few professions in the world that has a job important enough that we have to do it all times of the day or night. Maybe if you see it that way, you will start liking calls better.
My body doesn't seem to care about circadian rhythms,
. Just writing this makes me miss call, guess I'll just work all night tonight.