When I was younger, I suffered from down days a lot, as a result of working my way through university and simply doing too much. I learned that drinking didn't really help me too much, offering only a temporary fix from which I felt worse the next day.
Diet is related to depression. Especially food allergies. So, the minute I feel down, I start upping the amount of water I drink to wash out the toxins, and I avoid gluten, dairy products, and a few other things that I know I am borderline allergic to.
I also exercise. Usually I find a place that is near water and I run until I am ready to drop. In Columbus, that would be along the Olentangy or up Rt33. I also have a few good runs around Hoover Dam. Of course, there are lots of ocean runs here.
I think the water has a higher concentration of ozone, which reduces depression, and the run releases endorphins and also helps flush the toxins through the system. So, I find that I feel better after I run and rarely feel any lingering downer effects.
I also tune into BP when I feel down. I always find something amusing here or get distracted from my own problems by focusing on what one of the Buckeye teams is doing. BP is a real pick-me-up!