There are going to be times where you say to yourself, "That's it - I'm done, I want to quit." THIS is where you must keep punching. On the other side of quit is your next plateau. When the pain feels unbearable, this is when you call on every fiber of fight you have in your body. It's these moments where you grow the most.
Don't allow the illusion of failure to grab ahold of your passion - it's this battle that ultimately makes you who who are, and will define your journey. The only person who can stop you is ... you! Never allow that to happen.