I was never a "night person", but rather an "early bird" - I adapted just fine.
But it can definitely be hard at first.
I personally found it difficult to day sleep in many cases around the domestic system, only getting maybe 4 hours of sleep the first day, 4-6hr the two days after that, then generally the fourth day crashing out and getting 7-8hr from sheer fatigue. I also found falling asleep in the sleep rooms while sitting the sort hard to do (they are warmer than I prefer, and outside rooms have too damn much horn honking).
After a couple months online, I could sleep easier during they day and a bit better in sleep rooms.
I found making myself run every day kept me healthy, allowed me to sleep better at the end of a duty period, and the endorphins helped me "feel better" while working.
1. Sleep whenever you are tired
2. Eat as healthy as possible
3. Exercise!
4. Drink lots of water
5. Melatonin if needed
Just one guy's opinion...