All good advice above for sure. Keith, do you get any exercise? If not, start now. It's never too late to start. Just check out the links that I posted at the bottom. Plenty of people out there way older than you, staying active, as well as starting out way later.
The overall good feeling you get from exercise might just be the thing you need snap you out of what you're in. Not to mention the health benefits you get. And once you get going, it will definitely help energize you for many aspects of your life, whether it's fishing, hunting, or other activities.