It never fails, you get halfway through a project and the proverbial wall stops you cold. You know what needs to be done, there's time to do it right now, but you can't bring yourself to continue working.
There are some tricks you can try, like going for a walk, taking a power nap, having a cup of coffee. Those things may help, but in the end you have to push through.
That moment when you choose to either drive forward or "call it a night" can make all the difference. It can be hard, even overwhelming, but the more moments you push through, the easier it becomes.