When I found myself depressed and irritable on a diet, it seemed to be evidence that I was hungry. Is there any food or drink that you can try consuming to stave off that feeling, while still following the diet? As an example my diet allowed me to consume unlimited amounts of unprocessed fruit, so if I felt depressed and irritable, I could eat that until I felt better, and not hurt my diet at all.
I've ruled out hunger/low blood sugar as a simple causal factor. I imagine it's a combination of factors, but I'm annoyed at myself for implementing so many changes at once and not being able to determine efficacy or side-effects as a result.
If it's worth saying, but not worth its own post, even in Discussion, it goes here.