No matter how well we plan, we can't foresee everything. So things happen. Sometimes, you won't be able to perform as well as you wanted to. Otherwise, things happen that completely derail you.
Still... does those things kill your dreams? Only if you want them to. Or if you let them. Either way, the choice of keeping your dreams and goals alive rest with you.
When something sets me back, be it serious or relatively minor, I sit back, and take a deep breath. Then I take stock.
Does it affect me? How much? How?
Does it affect my dreams/goals? How much? How?
Will it affect how far I'm along on the road to my dreams/goals? How much? How?
Can I get back to where I was? Do I want to be where I was? What does that mean for me and my life, as well as those who depend on me?
Armed with these answers, I can decide what to do next - what I will do to start moving again. Even if it changed my dream, I redefine it and my goals and move towards that.
Because the one thing no one should want is to get mired in a place that gets them nowhere.
So has something ever set you back so far that you felt completely overwhelmed? Did you give up? If not, what did you have to do to keep going? If you did and want to start again, what do you need to do?