I've worked nights most of my nursing career. I rarely have a problem staying awake at work. Yes, I often get very tired but not to the point that my body is actually trying to go to sleep.
My current case is killing me. Regardless of how much sleep I get during the day, I often find myself fighting so hard to stay awake.
The environment certainly doesn't help! The parents want all lights of except for a tiny little lamp. The vent is making that lovely white noise. There is no TV for me to use. I could watch movies on my phone (Netflix) but my data plan isn't large enough and they won't allow the nurses to use their Wi-Fi. I'm a coffee drinker, but there's no coffee maker to use. .. actually they really don't want us using their kitchen after 11pm so that the house remains quiet. My thermos only holds so much... not that there is much room to put put my personal items without their dogs dragging it everywhere.
