Okay - so those are the fundamentals and it seems as though you deem yourself healthy. From your diet, I would assume you are vegetarian - is that correct? I am a vegetarian and here's the main thing I have to watch out for: getting enough iron. If I don't get enough iron, I am sleepy, cranky, tired-feeling, and just have a general malaise. This leads to less focus and less "patience" to deal with the mundane. Is it possible you are either anemic, borderline anemic or whether you are iron-deficient?