Fear is normal, it's part of being human it's not to be dismissed because fear is a great motivator.
The apostles on that little dingy were PANIC stricken to the point they were dysfunctional and couldn't think straight losing their witts and were most likely ready to bail out of the boat. I'm sure some of them left their finger nails stuck in the wooden sides they were so scared.
Jesus was essentially saying is "Don't give up when the chips (ships) are almost down or are down". Even Jesus was affraid, "Father, why has thow forsaken me",but he didn't give up. David was militarily out of his league when it came to facing Goliath, he didn't panic and give up. Paul said, "Finish the race". "Press on Christian soldier". "Nevva say nevva".