I have always had a problem running over 3 miles and I as I slowly build back up just getting to 3 miles can be a mental challenge. I was reading a magazine about setting up a mantra to help overcome those mental challenges.
I created this one for me - BE STRONG, EMBRACE POWER. I know I am physically strong, I just need to overcome the mental fears of failure. When I start to get stuck, I chant it in my head. Followed by - say it, believe it, become it.
It gives me the mental strength to push through when I think I am to weak to continue to run. So far it has been successful.