Yes, I identify with what you say. A year ago I nearly opted to hang my clogs up. For myself (and everyone is different), I turned this situation around by diet. I made sure I ate a breakfast before work (I never used to have anything beyond a strong black coffee). Now, it's fruit, cereal (soya milk), or toast (gluten free).
I kept watch on my food intake. As I follow a gluten free diet it was often troublesome. I drank far less alcohol (I had to!!) and ate far more fresh vegetables and fruit. Whereas before I would just have a chocolatey snack for lunch I made a decision to have fresh fruit. I drink plenty of water too.
I have far less fatigue problems, and I work long days too.
I think I will always be a jug head, and like my cider, but in 2012 it's now and again, not every night (ok, tonight is nearly my birthday so the rules say I'm allowed!)
I take vitamins and supplements. Vitamin D, vitamin B12, vitamin C. I never knowingly eat gluten.