At times, when things seem the hardest and most impossible, you lower your shoulder and run directly through a brick wall. You have it in you. We all do. It just SUCKS to be pushed to that point so we tend to avoid it.
I tend to crave those scenarios now. Earlier in life it was just the reality - times were hard and strength and resolve were needed to survive. Now I pay money to nearly kill myself in these exact (simulated) impossible situations. The irony is not lost on me and my psychotherapist thinks I'm pretty swell.