When you start out your day (or end your day) with something that most people can't do, it gives you a big rush of energy and confidence. You've had to work hard and earn the miles that you run every day. Knowing that I ran 3.5 miles yesterday and will run 6 miles tomorrow give me a huge confidence boost. This is something that I'm not really used to, but I like it.
Setting goals (whether it is time or distance) and accomplishing them drives me forward and gives me a better outlook on the day. Make sure that you are setting goals and pushing yourself. Soon you will be accomplishing things that you never thought possible. I do my first 10K next weekend!