There is nothing as terrible as being written off in life, either by others or by yourself.
A friend of mine told me a story about a man named Zane Grey, incredibly popular in the early 20th century. He began his career as a dentist, eventually he stopped being a dentist because his passion for writing kept driving him. Having begun writing his books, all he got was rejections for his works and was literally told that he had no business being a writer and as such should quit writing and go back to being a dentist.
It took him years though, but at 40, Zane finally got his first work published. He became an author of ninety books which sold over 50 million copies world wide.
Edward Teller said, "When you come to the end of all the lights you know, and it's time to step into the darkness of the unknown, FAITH is knowing that one of two things shall happen: Either you will be given something solid to stand on or you will be taught to fly."
Remember that darkness is what gives birth to light!