Thanks to everyone,
I will contact my union, I am a member so should be able to get some advice.
My diet is usually quite good, the balance with carbs and veg etc is close to the advice given by the dietician. My medication is steadily increasing though, it could be the stress that is maybe a factor now.
When on nights I work a 12hr shift, its very difficult to work for this long at night without ending up eating what adds up to an extra meal, I have reduced the portions to balance. The way the shift plan out its almost a continual change around.