When life gets tough it usually means you're in for something good. Friedrich Nietzsche (who knew some tough times) wrote:
Life always gets harder toward the summit—the cold increases, responsibility increases.
If you think about it, it's just common sense. Think about even physically going up a mountain. I'm sure you've seen those documentaries about climbing Mt. Everest. It's like everything is cool at Base Camp #1. Things are a bit tougher at Base Camp #2 but the climbers are hardy people, up for a challenge.
But when they leave base camp and begin the ascent for real, ah, that's when you seem some stressors in the climbers' lives. But if they want to reach the summit...
And isn't it exactly the same way in life? If you want to hang around Base Camp everything's cool. But is it really? There's a part of you that knows there's a summit out there and wonders what it would feel like to stand up there and survey the world below, wonders what it would be like to take such a major risk and make good on it.
So when things get tough, take that as a good sign that you're getting close to the top. Push on through those last couple steps. You'll be standing on a mountaintop and you can view, with great pride in your accomplishment, the vast valley below.