Hi I work night shift too and I did gain alot of weight from eating when tired to perk myself up and on the long ride home in rush hour traffic.
But now I still work nights and I have lost alot of weight .
I pay attention to my bodies cues and I stick to my plan.
Yes I have very broken up sleep and when I 'm off I switch back to a day schedule.
I try to work my shifts in a row so I only have I wasted day flipping back into a day schedule.
It is definitely harder to lose weight working nights but it also doable!
good luck hope you figure out a way to make it work for you,