When faced with a difficult task, the first decision is whether or not to commit -- to take on the task with the intent to succeed, or to quit before you even begin
If one decides to commit, having to grind through some tough spots becomes inevitable. When that happens, it's time to really just Suck it Up and push through (sensibly -- not to exhaustion, always living to fight another day).
One thing that one should not do however, is to stay mum about how difficult the task is. Shutting up is probably the fastest way to insanity -- we need an emotional outlet.
So, when faced with tough spots, talk about it. To your spouse, to your coworkers, to your cat, to your reflection, whatever... This is not to tell the world, but to tell yourself.
Once the complaints have been heard, and courage rises, facing that tough spot somehow becomes a matter of course.