In those moments of deep discomfort, you are the only one who gets to decide whether to stop or keep going. Think about that! You have the most powerful ability with inside yourself. You get to choose, No one else. 

If you decide to let someone else make that choice for you, then you have lost your free will. You have lost your most important ally and that is your autonomy. Never ever give up your ability for your freedom of choice. I tell my kids that above all else in the world, your autonomy and freedom of choice are the most important things you possess and own. Don't ever lose them or let them be taken away. Because when this happens you slowly start to lose your self. 

What are you going to choose to do in those moments of deep discomfort? Are you going to quit or are you going to put one foot in front of the other and finish. I suggest you finish because the scars of regret and quitting can last a lifetime. Just as the positive growth and emotions will last a lifetime because you chose to finish.