When you run, you may hit an imaginary wall. Long-distance runners talk about it as if it's some spiritual blockade they all must penetrate.
You aren't going to run a marathon today, but you may hit a less formidable wall of your own. Remember that it's all in your mind. It's your choice: Stop at the wall or crush your way through it. Either way, your life will go on. But, what kind of life do you want?