I ran 5 miles nonstop today. It was a slow pace, and I wasn't exhausted when I stopped. I think it's a pace (12:52/mile) that I can use to run the 1/2 marathon relay I'm signed up for on October 16th. There's certainly room for improvement, but if you remember, I just started running again this past May after a couple decades' worth of weighing over 300lbs.
I think I may have experienced my first runner's high today. It's something I want more of now that I've had it.