Four days til absolute destruction of my body

In four days I have to run 21 km across the capital city and across a finish line, to get a medal around my neck.

But training has been lackluster, weak, slow, short. The furthest I've ran is 12 km, and it was a struggle. And such a situation leads me with a lack of confidence, an uncertainty, as to whether or not I'm going to be able to do it.

I want that medal. More than anything. I want to sweat so much I'm drenched, and I want to cross that finish line. For myself.

Is it really mind over matter? Can I convince myself I'm going to do it, going to accomplish this huge hurdle I've been 'training' for, hoping for. I do not know.

Words of encouragement. Are needed.