I'm afraid it is almost entirely down to diet MC. Don't panic about "quite high levels" despite diet changes. How long has it been since you started the diet change and how are you "changing" your diet. One change at a time is best, you can't do it all at once and every change will take time to have an effect. It's important to eat regularly, don't skip meals.
The one person to consult, confide in is the nurse. Tell her of your concerns, that's what she's there for.