I can relate to all of those feelings. Last week I voluntarily gave up my full-time job as a painter for a construction firm. Not because I had a job offer with better pay, but because I have a calling to surrender myself for more time in ministry. When I look at the monthly bills and consider that I've almost cut my income in half, I'm thinking everything Peter may have thought.
When Jesus was standing on the surface of the Sea of Galilee, He said to Peter, "Come," and Peter got out of the boat. He didn't do as well as Jesus when it comes to walking on water, but he did make it to Him and back to the boat with Jesus' help. In our relationship with Christ, He calls us in much the same way. "Come, to where I am." We might think that's crazy and impossible, but we can do it with Jesus' help.
The thing that gets me about this account in the gospel is how so many people reprimand Peter for having such little faith. Well, I like to look at this way: If just a little faith helped a man get out of a boat and walk to Jesus on water, then what kind of faith did the eleven other guys have that stayed put in the boat?