Dreams?

Lately I have been thinking about my dreams and what it would take to achieve them. Then sometimes I actually start to see my dream come to life, but its ripped out from under my feet. I have dreams that I feel its something I'm suppose to do, or something that I've wanted to do all my life, then something stops it. Do you ever have giants in the way of your dreams? It happens to me all the time. Sometimes you have someone that discourages your dreams, telling you that it wont work, or that its not safe. You then start to doubt your own dream. It happens everytime. You leave your comfort zone and then not too long after that, you want to go running back to the warm fuzzy feeling. Why cant I just ignore the voices I hear and achieve my dreams? I'm still trying to figure out how to be strong enough or find other ways to achieve my dreams, but nothing's working.