Most people get depressed at some time or other, I now I do, even after years of being sober. My trick is to tell myself it will pass which it does and usually quite quickly when I am of that mindset. Are there any small changes you can make in your life. Sales is a manipulative business,but it doesn't make you a bad person and sometimes it is good to switch off from work mode. You sound a bit like your profession makes you feel a bit empty but if that's what you are good at, then that's what you are good at. Unless you can think of an alternative career, why don't you try to switch off by taking your mind off it with something else like a hobby? Cheer up xx