Never underestimate the impact of picking up bad habits with your diet and times of the day you eat. I got myself in a nasty disposition because I was staying so busy, I stopped eating properly and ate later in the evening, sometimes before I went to bed. That impacted my ability to sleep well which, adding the combination of high sugary/high processed foods got me pretty well displaced. Once the wife and I pinpointed that and I changed everything back to what it was, those issues resolved themselves. This may not be your circumstances, but its worth a review to make sure you're getting everything you need to function throughout the day, especially if your days get really involved.